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INTERVIEW
SensL believes thatits silicon technologywill replace PMTs
European photonicsreport warns onindustry funding
POLICY
AIRBORNE LIDARIN THE PIPELINEFOR GAS INDUSTRY
REMOTE SENSING
May 2006 Issue 139
INSIDECLEO/QELS/
PHASTPREVIEW
The European magazine for photonics professionals
OLEMayCOVER3 24/4/06 12.35 pm Page 1
NEWS5 Business Fibre lasers grab industrial market • Sony and NEC
partner to develop optical disc drives • Record Q3 for OmniVision
8 Analysis Photonics plan demands investment
9 Editorial Is your alarm bell ringing?
TECHNOLOGY11 Applications Liquid crystals ease bifocal strain • 3D profiling
sees defects in tyres • Terahertz QCLs image samples in 3D
14 R&D 3D negative refraction lenses trap particles • Surface plasmons squeeze light
16 Patents Tokyo court rules on case between Chi Mei and SEL
FEATURES17 Silicon detectors eye-up photomultiplier markets
Photomultiplier tubes are facing stiff competition from silicon-based low-light detectors. Jacqueline Hewett asks SensL’s Joseph O’Keeffe why he believes that silicon devices have what it takes.
21 Ultrafast pulses fool heat-seeking missilesA femtosecond laser’s ability to generate an intense electric field makes it ideal for disrupting missiles that use infrared guidance systems. Emmanuel Marquis of Thales Laser explains.
24 Helicopter LIDAR speeds up pipeline inspectionAn airborne LIDAR system could help to revolutionize gas pipeline monitoring. James Tyrrell finds out more.
27 Slowing light in optical fibres sees fast progressLuc Thévenaz and Miguel Gonzalez-Herraez chart recent progressin slowing down light to produce optical delay lines and describe some of the new challenges facing developers of practical devices.
31 Multiphoton approach shapes ultrafast pulsesCoherent explains how a new method of phase and amplitude control delivers near-transform limited pulses.
34 Robust mirrors take on demanding applicationsSelecting the right mirror for the right job is no trivial task. MichaelCase and Mark Dykstra guide OLE readers through the process.
SHOW PREVIEW36 CLEO/QELS/PHAST
Highlights • Show products
PRODUCTS41 3D scan system• Dichroic filters • Modular microscope
REGUL ARS46 People/Sudoku
EDITORIALActing editor Jacqueline HewettTel: +44 (0)117 930 [email protected]
News editor James TyrrellTel: +44 (0)117 930 [email protected]
Science/technology reporter Darius NikbinTel: +44 (0)117 930 [email protected]
Production editor Alison GardinerTechnical illustrator Alison Tovey
EUROPE/ROW SALESGroup advertisement manager Adrian ChanceTel: +44 (0)117 930 1193 [email protected]
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© 2006 IOP Publishing Ltd. The contents of OLE donot represent the views or policies of the Institute ofPhysics, its council or its officers unless so identified. Printed by Warners (Midlands) plc, The Maltings, West Street, Bourne, Lincolnshire PE10 9PH, UK.
I ssue 139 May 2006 Contents
Camera phones fuel growthat CMOS expert OVT p7
Terahertz quantum cascadelasers reveal defects p13
Ultrafast lasers confuse IR-guided missiles p21
Our product guide explainshow to buy mirrors p34
INTERVIEW
SensL believes thatits silicon technologywill replace PMTs
European photonicsreport warns onindustry funding
POLICY
AIRBORNE LIDARIN THE PIPELINEFOR GAS INDUSTRY
REMOTE SENSING
May 2006 Issue 139
INSIDECLEO/QELS/
PHASTPREVIEW
The European magazine for photonics professionals
For the latest news on optics and photonics don’t forget to visit optics.org
Cover (Adlares, E.ONRuhrgas) Helicopter-mounted LIDAR kitinspects gas pipelines. p24
OLEMayContents3 24/4/06 2.24 pm Page 3
Stanford Research Systems1290-D Reamwood Ave. Sunnyvale, CA 94089 · www.thinkSRS.comPhone (408) 744-9040 · Fax (408) 744-9049 · [email protected]
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Other lock-in amplifiers ...starting at $2745 (Int’l list)
The SR830 is the most widely usedlock-in amplifier in the world. Itmeasures signals with greateraccuracy, higher stability, and betternoise rejection than any other lock-in.With over 100 dB dynamic reserve,5 ppm stability, and 0.01 degree phaseresolution, the SR830 will handle themost demanding applications. It hasconvenient auto-measurementfeatures, a wide selection of timeconstants, and a built-in source with80 dB spectral purity. Best of all, it’s affordable.
• 0.001 Hz to 102 kHz frequency range
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• Auto-gain, -phase and -reserve
• Harmonic detection (2F, 3F, ... nF)
• Time constants from 10 µs to 30 ks (6, 12, 18, 24 dB/oct. rolloff)
Fibre lasers grab industrial market
NEWSBUSINESS 5 ANALYSIS 8 EDITORIAL 9
5OLE • May 2006 • optics.org/ole
FIBRE LASERS
Fibre laser sales will grow by over35% per year from $140 m(7114 m) in 2005 to $680 m in2010, in an industrial laser marketthat will grow just 9% per year to$2.8 bn over the same period.
This remarkable shift is just oneof the conclusions of a new reportfrom Strategies Unlimited (SU), theoptoelectronics market researchfirm. Fibre-laser suppliers can seizemarket share from solid-state andother types of lasers in several keyapplications that will see steadygrowth in coming years, states theFiber Laser Market Review andForecast 2006.
To put things in perspective, theindustrial laser market includessources from about 10 W (formarking, for example) to tens ofkilowatts (for welding and cuttingmetal). Fibre lasers are not com-peting in applications that employdiode lasers, such as thermal print-ing or cosmetic hair removal.
The fibre laser is primarily a sub-stitute for the diode-pumped solid-state laser, but in time, it isexpected to make in-roads in othersectors. These will include sensingapplications requiring only a fewwatts to much higher powers suchas the 36 kW fibre laser that IPGPhotonics sold to MitsubishiHeavy Industries in 2005. Thehighest unit volumes are found inthe low-power marking appli-cations, but as price scales withpower, so much of the revenue willbe in the high-power regime.
According to the report, IPGPhotonics has the dominant mar-ket share in fibre lasers, makingmost of its own key components.SPI Lasers is another established,dedicated fibre-laser supplier. Astriking feature of the fibre-lasermarket is that the usual large (gasand semiconductor) laser suppli-ers are generally not prominentsuppliers of fibre lasers.
Laser market-leaders, such asCoherent ($500 m sales, SU esti-mates), Trumpf ($450 m), Rofin-Sinar ($380 m) and Newport($175 m), do not currently offer afibre laser product. JDSU manufac-tures fibre lasers, but does not havestrong market share.
In contrast, privately held IPGPhotonics approached the $100 mrevenue mark in 2005, placing itamong the top 10 laser manufac-turers in the world. And if businessgoes well in 2006, it could beamong the top five, SU believes.
The fibre-laser market is roughly
evenly split between North Amer-ica, Europe and Asia. But as themarket is growing so fast, SU saysthat it is hard to see a trend yet. Theanalyst adds that it is important toremember that the fibre laser cus-tomers are often the toolmakers,sometimes the end-users. The end-users usually buy the complete toolwith the fibre laser inside, and maybe on another continent from thetoolmaker. The end-users also seemto be roughly split among the threemajor regions.
So will the market see other typesof laser company start to developfibre lasers; or try to buy up fibre-laser makers; or even vice-versa?
“I cannot predict what will happen specifically,” says TomHausken, director of componentsresearch at Strategies Unlimited,“but I am certain that one or morecompanies will make a move. It isremarkable that IPG is now amongthe top 10 laser companies in theworld, in revenues, and may be
among the top five by the end of2006. JDSU aside, none of theother major laser companies evenoffers a fibre laser. It’s hard toimagine that they will just stand byand watch this continue.”
The promising outlook for fibrelasers is tempered by several loom-ing uncertainties, however. Goodexecution on IPG’s part could forceother fibre-laser suppliers into smallniche markets. Any mis-step by IPGwould open up opportunities forsuppliers of fibre lasers and otherlasers, including the new thin-disklasers. Further ahead, improve-ments in the price and performanceof direct-diode systems could helpsuppliers of those systems capturemarket share from fibre lasers,although in some cases the lasersuppliers may be the same.
“The fibre laser is the next gen-eration of laser technology thatprovides most of the advantagesand eliminates many of the disad-vantages of the conventional solid-state laser,” explains Hausken.“However, the machine-tool busi-ness that these lasers serve is anotoriously cautious industry. Theend-user isn’t impressed with thelaser itself, only with what thewhole system can do.”
The Fiber Laser Market Reviewand Forecast 2006 is availablenow from Strategies Unlimited. Seewww.strategies-u.com.
Matthew Peach is a contributingeditor on OLE and optics.org.
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High in fibre: fibre laser sales will account for 25% of industrial sales by 2010.
As OLE went to press, Osram OptoSemiconductors announced that ithad developed laser bars with anelectro-optical conversion effi-ciency of 64% in its laboratories.The bars are prototype versions ofa new generation of diode lasersthat the German chipmakerexpects to see commercialized two
years from now.In the laboratory demonstra-
tion, the 808 nm lasers, which arebased on a GaAs substrate, deliv-ered an output power of 120 W.The company’s current genera-tion of diode lasers produces halfthat power with a conversion effi-ciency of 55%.
The high-efficiency diode lasersare being developed in collabor-ation with Dilas, a fellow Germancompany that has developed anactive water-cooling system. Thetwo firms are working under aresearch project initiated by theGerman government. Its key targetis the production of 110 W sourceswith a lifetime in excess of20 000 h in continuous-wave orlong-pulse operating mode.
Once the laser bars are commer-cialized, they will be used to opti-cally pump solid-state lasers forindustrial applications such aslaser welding of metal parts usedin automotive manufacturing.
“With the new, more powerfullasers, not only can the system out-put be increased, but the systemscan be made smaller and more reli-able for the equivalent output,”said Osram in a statement.
Osram hits efficiency milestone for808 nm lasers: 64% in the laboratory
DIODE LASERS
Stra
tegi
es U
nlim
ited
OLEMayNEWS5-9 21/4/06 3.26 pm Page 5
Sony and NEC partner todevelop optical disc drives
NEWSBUSINESS
DATA STORAGE
6 OLE • May 2006 • optics.org/ole
Thetrue measureof laserperformance
www.ophiropt.comLaser Measurement
Super StoreMulti Language
Web SiteLaser MeasurementInformation Center
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Sony and NEC agreed last month toestablish a joint venture (JV) com-pany to further develop optical discdrives (ODD). The stockholdingsplit between the partners is Sony55% and NEC 45%.
Sony says that the new com-pany, Sony NEC Optiarc Inc, will byvirtue of Sony’s and NEC’s marketshares immediately become thenumber two ODD manufacturerbehind Hitachi-LG Data Storage,by jumping ahead of Toshiba Sam-sung Storage.
Shinichi Yamamura, formerlydeputy president of Sony’s VideoBusiness Group, is to serve as thepresident of the new operation.
The 350-strong new company,which is headquartered in Tokyo,Japan, is expected to generate busi-ness worth ¥220 bn (71.5 bn),based on Sony and NEC’s com-bined sales of ODDs in 2004.
“Sony and NEC believe that suchco-operation will be complemen-tary”, Masahiro Toyama, senior
marketing manager at Sony Semi-conductor & Electronics Solutionsin Europe, told OLE. “We canexpect great synergy by thismerger in terms of procurement ofkey components, development,production and even sales.”
NEC has substantial ODD engi-neering design know-how andcompetitive large scale integrationof electronic integrated circuits,while Sony has the optical pickupand drive design knowledge. Thefirst batch of products will be DVDwriters similar to the models Sonyis currently selling.
Considering that NEC is backingthe HD DVD format while Sony is amember of the Blu-ray Disc Asso-ciation, where does Toyama seethis storage technology going? “Itis possible that the JV will developboth competitive Blu-ray and HDDVD technologies. But it would bedifficult to develop a drive that sup-ports both formats,” he said.
Sony remains convinced that
the Blu-ray Disc format has thebiggest potential to become thenext major optical storage format.Sony Recording Media & EnergyEurope has just launched what itbelieves to be the first Blu-ray Discmedia in Europe. The Sony ITPeripherals division plans tolaunch a Blu-ray disc drive for PCsin the second half of 2006. Thefirst Blu-ray Disc players have justbeen announced in the US.
“The DVD format is widelyaccepted but the next step in opti-cal disc migration is to have a sig-nificantly higher capacity thatallows high-definition recordingand higher quality such as in TVpictures,” Toyama continued, “butwhat is really important with next-generation optical technology ishow to extend the market from itscurrent PC-based position to con-sumer applications and games.”This is expected to include thedelayed PlayStation 3, expected tobe released in November 2006.
FI B R E L A S E R S
Quantel of France and two financialbodies have invested a total of71.3 m into short-pulsed fibre-laserspecialist FEMLIGHT. Quantel andFEMLIGHT will now team up todevelop a fibre-laser product forindustrial applications that isscheduled to launch in the secondhalf of 2007. Quantel says thisinvestment reaffirms its strategicdecision to become a significantplayer in the fibre-laser market.
L A S E R C U T T I N G
Rofin-Sinar Technologies hasacquired a 40% stake in H2BPhotonics of Germany. Furtherdetails were not disclosed. H2Bspecializes in laser-based systemsfor cutting brittle metals such asglass, which are used for plasmascreen displays, windows andautomotive parts. H2B was foundedin 2005 as a spin-off from LaserZentrum Hanover (LZH), Germany.
AU T O M O T I V E L I G H T I N G
Philips Electronics of the Netherlandsis investing around 730m in itsautomotive headlighting competencecentre in Aachen, Germany. Theinvestment will pay for theinstallation of an ultra-modernproduction line for Philips’ xenon arclamps. The company says that xenonheadlights produce 3× as much lightand consume 50% less energy thanthat of traditional halogen headlights.
L A S E R S
Coherent, US, has opened an officein Seoul, Korea, to provide furthersupport to the rapidly growingdomestic laser market.
IN BRIEF
Feet in both camps: it is possible that the Sony–NEC joint venture will develop both competitive HD DVD and Blu-ray technologies.
OLEMayNEWS5-9 21/4/06 3.19 pm Page 6
Record Q3 for CMOS sensordeveloper OmniVision
NEWSBUSINESS
IMAGING
7OLE • May 2006 • optics.org/ole
"…Let there be light: and there was light." (Genesis 1:3) www.ophiropt.com
OmniVision Technologies (OVT),Sunnyvale, CA, US, a developer ofCMOS image sensors, has reportedrecord financial results for its thirdfiscal quarter of 2006, to 31 Janu-ary. Revenue for the quarter was arecord $137 m (7110 m), up from$127 m the previous quarter, andup 34% on the same period in 2005.
Revenue for the first ninemonths of fiscal 2006 was$360 m, compared with $285 mfor the same period in 2005, a riseof 26%. These sales generated anet income of $67 m, up 13% onlast year’s equivalent. OVT’slargest market continues to be themobile handset market; the com-pany’s range of image sensorsdesigned specifically for cameraphones has clearly benefited fromthe overall strength of this market.
The third fiscal quarter of 2006saw OmniVision increase its rangeof product shipments to multipleleading toy and video game con-sole vendors. The company alsobegan shipping to top-tier automo-tive parts suppliers.
“We are pleased that OmniVi-sion has delivered another quarterof revenue and earnings growth,”said Shaw Hong, OmniVision’spresident and CEO.
“Beginning in the July quarter,our new 2.0 Mpixel sensor willstart shipping in volume to largehandset clients and we anticipatesignificant demand for our ultra-thin VGA and 1.3 Mpixel sensors.”
“The majority (75%) of our rev-enue comes from the phone handsetmarket,” says OVT’s investor rela-tions director Steven Horwitz. “Webelieve that mobile phones will con-tinue to be the dominant marketand our biggest revenue generator.”
The company says that thestrength of its key market is basedon growing demand for moresophisticated handsets. “Approxi-mately 800 million handsets weresold in 2005 and about 50% ofthese had built-in cameras,” saysHorwitz. “In 2006, the marketexpects the total figure to rise to 900million handsets, of which 55–58%will feature a built-in camera.”
Another reason for OmniVision’sextended spell of success is thehandset market’s increasingdemand for higher resolution cam-eras. “Our VGA sensors [640×480pixels and 256 colours] have typi-cally represented a higher percent-age of our product mix for thehandset market, but during the fis-cal third quarter we experienced a
surge in sales of our 1.3Mpixel sen-sors. We believe that 2.0 Mpixelperformance at a 1/4-inch size willreally push such chips into thisexpanding market by providinghandset manufacturers with aclean upgrade path from1.3 Mpixel sensors.”
Prior to the handset market tak-ing off, OVT says it had enjoyed sig-nificant success in the digital stillscamera market with its 3.0–5.0Mpixel sensors. But that sector isnot growing that fast any more.
The company believes that itcan now increase its CMOS imagesensor sales in commercial sys-tems. Horwitz explains, “Overall,we can provide a more cost-effec-tive solution than the CCD sensorscurrently used in commercial sys-tems without compromising qual-ity. CCD imaging sensors requirefour chips in silicon – image sen-sor; converter; amplifier; and sig-nal processor – which we can do injust one integrated CMOS chip.Moreover CMOS is inherently eas-ier to mass produce.”
OVT has also started realizingrevenues from the automotive sec-tor, such as with Hella, the Germanvehicle component manufacturer.Applications here include rear-viewcamera systems which project on tothe sat-nav screen; lane departurewarning systems; rain sensors,auto-light dimmers; smart airbags;and camera system replacementsfor side-view mirrors (see photo).
MEMSOlympus of Japan and MovazNetworks of the US have formed ajoint venture called OlympusMicrosystems America to provideMEMS-based technologies tooptical equipment suppliers. Basedin San Jose, California, the newcompany predicts gross sales of¥6 bn (741 m) within five years.
DI S P L AYS
Light Blue Optics, UK, has receiveda £75,000 (7108 500) R&D grantfrom the DTI/EEDA, which it will puttowards the development of aprototype miniature colourprojector. The firm now plans toexpand its engineering team and islooking for optical and hardwaredevelopment engineers for itsCambridge facility.
OLEDS
Novaled, Germany, and CibaSpecialty Chemicals, Switzerland,have agreed to collaborate on thedevelopment of OLED materials. Cibawill continue to produce the uniqueorganic dopant and transportmaterials developed by Novaled. Thetwo companies will also jointlydevelop future OLED products andplatforms based on Novaled’stechnology and materials.
MI C RO D I S P L AYS
Icuiti of the US has come up withvideo eyewear suitable for themuch-hyped mobile TV sector. Thewearable unit, which features two640×480 VGA resolution LCDpanels, plugs into the mobilephone’s AV port to give a virtual 42-inch display.
IN BRIEF
Enhanced vision: next year, a new EUstandard will require all truck and busdrivers to have a 360° view.
Om
niVi
sion
OLEMayNEWS5-9 24/4/06 10.39 am Page 7
Photonics plan demands investment
NEWSANALYSIS
POLICY
8 OLE • May 2006 • optics.org/ole
Increased public and privateinvestment and a more coherentapproach to organization arerequired if Europe’s photonicsindustry is to remain competitiveinternationally. These are just twoof the conclusions of a new reporton Europe’s photonics R&D andbusiness activities.
The first photonics StrategicResearch Agenda (SRA) “Towardsa Bright Future for Europe” wasunveiled on 4 April at PhotonicsEurope, which was held in Stras-bourg, France.
The 160 page agenda was writ-ten by the Photonics21 industrygroup. This body involves morethan 350 experts from 27 coun-tries, including 120 research cen-tres and companies such asAlcatel–Thales, Bookham Technol-ogy, Fraunhofer Institutes, INTEC-IMEC, Jenoptik and Trumpf Laser.
“Considering the massive effortsin the USA and Asia, providing forsufficient European R&D invest-ment in photonics is an indispens-able prerequisite for the futuresuccess of the European photonicseconomy and its competitiveness,”the report states.
Private R&D investment by theEuropean photonics industry cur-rently amounts to 73.3 bn perannum, which represents about
9% of the overall annual turnover.However, European public invest-ment in photonics is much lower:the current ratio of public-to-pri-vate investment in collaborativephotonics R&D is about 1:15,which is extremely low comparedto other industry sectors.
Presenting the SRA, Alexandervon Witzleben, Photonics21 presi-dent (and managing director ofJenoptik), asked Viviane Reding,the European Commissioner forInformation Society and Media, fora combination of funding and pol-icy reform with regard to the pho-tonics sector.
Photonics21 believes that thethreat from US and Asian compa-nies against European developers
of photonics systems is increasing.“Although Europe’s photonics in-dustries have some coordinationat the national level, we need bet-ter coordination across Europe,”said von Witzleben.
“Europe is in a strong positionin the photonics market overallbut we need to speed up andincrease our R&D efforts. As Asia– in particular – improves in thisarea, Europe will not stay wherewe are without taking action,” hecontinued. “The US and Asiaspend four times as much asEurope on R&D in the field of pho-tonics. Those countries have alsoadvanced considerably in recentyears thanks to their concertedand well-structured policies.”
Photonics21 believes thatEurope’s ability to remain compet-itive in the high-tech arena is “atstake”, as is the competitiveness ofmajor European photonics compa-nies who employ a large segmentof the continent’s leading re-searchers, scientists and engineersin this field.
For example, Europe seems to belosing the game to Asia in the fieldof LCD displays. On the otherhand, in some areas where therehas been a lot of public investmentin photonics, European companiesenjoy leading positions. These
include: solid-state lighting, whereEuropean companies supply morethan 30% of the world market,and laser-assisted manufacturing,where EU-based companies hold atleast 50% of the world market.
Commissioner Reding said thatshe accepted the implications ofthe SRA. Ultimately responsible fortechnology funding recommenda-tions to the EC, she emphasized theneed for Europe to link research tothe delivery of innovation, growthand jobs. “Europe must concen-trate its efforts on areas that showgreat promise and where a greatreturn on investment can beexpected,” she said.
The commissioner acknow-ledged that photonics is one ofthese areas. She added that whileEurope already employs more thantwo million people in photonicsand related industries, the potentialfor photonics-enabled advance-ments in the areas of health care,lighting, security and other appli-cations offers “unlimited potentialfor job creation and economicdevelopment in Europe”. She alsoexpects that the strategic impor-tance of photonics technology willcreate new markets.
Matthew Peach is a contributingeditor on OLE and optics.org.
The European photonics industry requires more investment from both private and public sources, andbetter management if it is to maintain its strong position. Matthew Peach finds out more.
Commissioner Viviane Reding receivedthe first draft of the SRA at PhotonicsEurope, Strasbourg, France, in April.
1. European photonics industriesand academia need to join forcesunder a strong umbrella. The wayto achieve this is through closercollaboration between thephotonics industry, research, thefunding agencies and the EU. 2. Increased public and privateinvestment in photonics is needed.At Photonics Europe, Photonics21member companies revealed plansto increase their own spending on
R&D by 7330 m per annum. Themember companies demandedthat the increase be linked with astrong focus on photonics in theSeventh Framework Programme(FP7) and an associated doublingof European Union funding. 3. Clear responsibility forphotonics within the EuropeanCommission is needed.4. A mirror group involving therelevant public authorities and
funding bodies throughout Europeneeds to be installed. In spite of thediversity of the disciplines involvedand the fields of applicationaddressed, there is an urgent needfor a common approach forphotonics R&D in Europe. 5. Leading-edge research andinnovation requires involvementand co-operation along the wholeeconomic value chain – fromresearch to products.
6. Cross-sectoral issues need tobe linked with application-oriented issues. 7. Synergies between differentfields of application have to beutilized.8. Substantial attention should begiven to the fact that photonicscommunities and coalitions areemerging worldwide (e.g. in the US,Japan and Australia) while photonicsin Europe is still fragmented.
Key recommendations of the SRA: “A common approach for R&D in Europe”
Phot
onic
s21
OLEMayNEWS5-9 21/4/06 1.33 pm Page 8
Is your alarm bell ringing?
NEWSEDITORIAL
OLE • May 2006 • optics.org/ole
The European photonics industry received awake-up call last month when the first “Strate-gic Research Agenda” was unveiled at Photon-ics Europe. Entitled “Towards a brighter futurefor Europe”, the document could easily have asub-title along the lines of “How to protect thestrength of European photonics” or “Theindustry is at stake – we must act now”.
Photonics21’s strongly worded 160-pagereport paints European photonics in avulnerable light. It recommends two clearremedial actions: deliver greater public andprivate investment to compete with strongUS and booming Asian industries; andimprove the coordination between Europe’sphotonics players.
Given that the report was authored by big-hitters including Jenoptik, Bookham,TRUMPF and Carl Zeiss, one can only hopethat the report rings alarms bells with thepeople in a position to make these changes.
Worryingly, the report states that the USand Asia spend four times as much as Europeon photonics R&D. It goes on to explain thatthe funding of photonics research in the USand Asia is superior both in terms of thesheer amount of cash that is available and amore structured approach.
“Considering the massive efforts in the USand Asia, providing sufficient European R&Dinvestment in photonics is an indispensableprerequisite for the future success of theEuropean photonics economy and itscompetitiveness,” says the report.
The Photonics21 members plan toincrease their own research spending by7330 m per year and are calling for adoubling in EU funding.
Things need to change as Europe cannotafford to go on in this fragmented fashion.Only a well-thought-out approach will seeEurope hold onto its competitive advantagein areas such as solid-state lighting andmaterials processing now and in the future.There are also more than two million jobs onthe line in photonics and related industriesacross Europe.
Now that the report has been published, it’stime to put the words into practice. To readmore about the report’s recommendations,see the article on p8 (opposite). What are yourthoughts on the report? Has it come at just theright time or is it a case of too little, too late?
Jacqueline Hewett, acting editorE-mail: [email protected]
“The reportpaintsEuropeanphotonicsin avulnerablelight.”JacquelineHewett
OLEMayNEWS5-9 21/4/06 3.29 pm Page 9
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Liquid crystals ease bifocal strain
TECHNOLOGYAPPLICATIONS 11 R&D 14 PATENTS 16
11OLE • May 2006 • optics.org/ole
VISION
Do you wear bifocal spectacles andget frustrated with shifting yourgaze between the upper and lowerlenses as you switch from distant tonear vision? If so, help could soon beat hand thanks to a new lens beingdeveloped by scientists in the US.
The lens consists of a layer ofliquid crystal between two glasssurfaces, the focusing power ofwhich can be changed by alteringthe voltage applied to the lens. Thelens has to be manually switchedon and off to change focus, but theresearchers say the work couldlead to lenses that automaticallyadjust their focus depending onwhere the user is looking (Proc.Natl. Acad. Sci. to be published).
As we get older, our eyes becomeless flexible and often lose theirability to shift focus from distant tonear objects. This phenomenon,known as presbyopia, is thought toaffect more than 90% of people.Bifocal lenses, which contain twodifferent areas of glass, are a com-mon solution. However, users stillneed to move their gaze betweenthe upper and lower lenses as theyswitch from looking at distant tonear objects. Looking downwardsthrough the lens can make youdizzy and give you a headache.
Guoqiang Li and colleagues fromthe University of Arizona and co-
workers at the Georgia Institute ofTechnology, both US, have devel-oped a lens that overcomes theseproblems. It comprises a flat, 5 µm-thick layer of liquid crystal sand-wiched between two layers of glassthat are coated with concentricrings of tiny, transparent indium-tin-oxide electrodes.
When the lenses are “off ” andno field is applied, the lens can beused to look at distant objects. Butapplying a voltage of less than 2 Vto the electrodes changes the ori-
entation of the liquid-crystal mol-ecules, which in turn alters therefractive index of the crystal. Thisallows the lens to switch its focus-ing power so that a near object canbe viewed almost immediately.
When the voltage is removed,the lens reverts to its original non-focusing configuration, which alsomeans that it is safe to use fordistant-vision activities such as dri-ving should the power source fail.
Li and colleagues have foundthat their lens performs well for
both near- and distant-vision tasksby testing prototype glasses. Atpresent, the applied voltage needsto be switched on and off for thelens to change focus. Ultimatelythe device will work automatically“like an auto-focusing camera”,say the researchers, thanks to abuilt-in rangefinder. And al-though the glasses are hardly theheight of fashion, the researchershope that industry will design bet-ter looking adjustable-focus lensesin the future.
One of the UK’s most spectacularlighting displays – the newilluminations at the Clifton Suspension
Bridge in Bristol – is based on anintegrated array of thousands of LEDs,fluorescent tubes and lamps.
The display was switched on forthe first time on 8 April as part of thecity’s celebration of the 200thanniversary of the birth of pioneeringengineer and bridge designerIsambard Kingdom Brunel.
The illuminations were designed byarchitectural lighting specialistsPinniger & Partners, and consist ofvarious types of lighting technologies.
Along the length of the chains, fromwhich the 214m-long bridge issuspended, are more than 3000 1 WLEDs, arranged in groups of three.Each set focuses on a section of thechain and throws into relief the giant
nuts that connect the links.Fluorescent tubes beneath the
handrail not only illuminate thewalkway for pedestrians but alsosilhouette and emphasize thedelicate design of the iron lattice thatruns the length of the bridge.
Conventional lamps, concealedwithin the arches of the two 26 m-hightowers at each end of the bridge, aresaid to reinforce the three-dimensional aspects of the design inways that were impossible with theprevious “on or off” system. In the newsystem a touch-screen panel controlsa variety of pre-programmed displays.
The lenses in these glasses consist of a flat, 5 µm-thick layer of liquid crystal sandwiched between two layers of glass that arecoated with concentric rings of tiny, transparent indium-tin-oxide electrodes. The lenses change focus as a voltage is applied.
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OLEMayTechnology11-16 21/4/06 1.15 pm Page 11
3D profiling sees defects in tyres
TECHNOLOGYAPPLICATIONS
INSPECTION
12 OLE • May 2006 • optics.org/ole
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Continental Tyres of Germany hassolved an in-line inspection prob-lem with a laser-based, non-contactprofile-measurement technique.Rather than just sampling the pro-duction line, the system inspectsindividual tyres in less than 1 s forthe slightest bulge, recess or othersurface defect that could compro-mise vehicle safety.
The new inspection system isbased on three ScanControl 28002D/3D laser profile sensors fromGerman firm Micro-Epsilon. Thecombined laser transmitter andsensor units are then mounted ona test rig developed by systemsintegrator and machine builderMicroStep of Slovakia.
The ScanControl sensors meas-ure the profile of the tyre with anon-contact laser line, on whichmultiple measurement points – upto 256 000/s – can be acquiredand analysed.
“Our breakthrough with thethree ScanControl 2800 sensors iscombining the laser source andreceiver into a single unit,” ChrisJones, managing director ofMicro-Epsilon UK, told OLE. “Thekey to this is our solid-state trian-gulation technology. We can cor-rect, in real time, for changes intarget geometry because of thetrapezoid nature of the laser lineoutput. We have developed a preci-sion measurement system ratherthan just a vision system.”
Previously, Continental employedan inspection method relying oncapacitive sensors and laser-basedoptical point sensors. Compared
with the new laser line-scanmethod, capacitive sensing detectsover a relatively large measure-ment locus meaning that patterns,symbols or legends on the tyremight not be distinguished fromreal defects.
With laser point or spot sensors,not only would multiple sensorshave to be used to acquire thesame surface defect data, but thesensors could not cope with the
high throughput rates of tyres onthe test rig. The sensors also hadproblems with the reflective prop-erties of newly produced, shinyrubber tyres.
The ScanControl 2800 sensorhas an integrated, sensitive CMOSarray, which allows inspection ofalmost any shiny, reflective or trans-parent surface, independent ofreflections. Using customized soft-ware algorithms, logos and symbols
on the tyre can be removed whenthe data are analysed.
Each ScanControl transmitter/sensor features a class 2M 15 mWsolid-state visible laser that pro-jects a red 675 nm beam onto thetyre surface from a distance ofabout 250 mm. The measurementsystem consists of three sensorsand a controller. Measurementdata are output from the controllervia a FireWire interface to themanufacturer’s in-house devel-oped analysis/evaluation software.
Along with distance information(z-axis), the controller also calcu-lates the true position along thelaser line (x-axis) from the cameraimage and outputs both values inthe sensor’s 2D co-ordinate system.A moving target or a traversingsensor generates a 3D representa-tion of the object being measured.
MicroStep’s test rig receivestyres automatically from the pro-duction line. These are held inplace by a fixture or gripper, whichrotates each tyre through 360° inunder 1 s. During this time, thethree sensors inspect the threesides of the tyre walls for defects,taking measurements in real time.
Other potential applications forthe ScanControl 2800 includecontour measurement, robotguidance, door gap alignment,position measurement, rail profile,groove measurement, co-plan-arity measurement and flatnessmeasurement.
Matthew Peach is a contributingeditor on OLE and optics.org.
Tyres are held in place and rotated through 360° in under 1 s whilst the three lasersensors perform real-time inspection of the walls for potentially lethal defects.
Micro-Epsilon
OLEMayTechnology11-16 24/4/06 11.00 am Page 12
Terahertz QCLs image samples in 3D
TECHNOLOGYAPPLICATIONS
IMAGING
13OLE • May 2006 • optics.org/ole
A team from the UK has unveiledwhat it says is the first imaging sys-tem to combine high-power tera-hertz (THz) quantum cascadelasers (QCLs) with a 3D imagereconstruction technique. Havingtested their system on polystyrenesamples, the researchers believethat future applications includecharacterization of pharmaceuti-cal products, security and qualitycontrol (Optics Express 14 2123).
Lynn Gladden from the Univer-sity of Cambridge and her col-leagues from the universities ofLeeds and Manchester adoptedthe same approach to that used inX-ray computed tomography. Thisinvolves acquiring a series ofcross-sections through a sampleand processing them to obtain a3D reconstruction.
“Important considerations werethe available power, the opticaldesign to provide a well-colli-mated, small diameter beamthrough the sample and the analy-sis of the data,” Gladden told OLE.“Using a QCL addressed the issue of
available power directly.”The researchers grew a THz QCL
based on a GaAs-AlGaAs hetero-structure by molecular beam epi-taxy. Emitting at 2.9THz, the deviceproduced 250 ns pulses at a repeti-tion rate of 80 kHz and offered apeak pulse power of 70mW.
The QCL was mounted on acryostat and its emission wasfocused on to the sample using aset of parabolic mirrors. Motorized
stages translated the sample andthe transmitted radiation was col-lected by a Golay cell.
According to Gladden, theimage resolution is typically800–1100 µm and is governed bythe beam focus over the thicknessof the sample. Although it takesaround 15 min to acquire one sliceof an image, the complete recon-struction takes only a few seconds.
“The limitation of the current
system is very much its ability toaccount for reflection and refrac-tion of THz radiation,” explainedGladden. “The Radon transformalgorithm used in X-ray tomogra-phy limits us to studying materialswith a refractive index of less than1.5 if artefact-free images are to beobtained.”
The team now hopes to findways to account for scattered radi-ation in the reconstruction andincrease the refractive index ofmaterials that can be studiedquantitatively.
“Employing more advancedoptics giving a non-diffractingpencil beam closer to the diffrac-tion limit will be a future goal,” saidGladden. “We are also studyingmicrobolometer arrays for paralleldetection. This would remove theneed to scan the beam across thesample. Increasing THz QCL pow-ers will also decrease data acquisi-tion times.”
This project was performedunder the RCUK Basic TechnologyProgramme.
QCL incryostat
parabolicmirrors
sample Golay cell
Liquid-based, optical waveguidesthat can be reconfigured in realtime are being developed by a teamat Harvard University, US. Thedevice is said to be much less sensi-tive to manufacturing flaws thanksto the optically smooth liquid inter-face between core and cladding flu-ids (Appl. Phys. Lett. 88 061112).
“One advantage of a liquid wave-guide is that the optical and physi-cal properties of the core andcladding can be changed simply byintroducing different fluids,” SindyTang told OLE. “Varying the ther-mal gradient across the two com-ponents gives another parameterto control the waveguide’s output.”
In the Harvard device, the coreand cladding liquids are identical(water), but introduced into the
microfluidic channel at differenttemperatures to provide a contrastin refractive index. Using the sameliquid for both components of thewaveguide means that the fluidsare easy to reclaim and re-use.
The core liquid was supplieddirectly at room temperature(21 °C), whereas the cladding fluidwas preheated and injected at vari-ous temperatures from 30 to 80 °C.
The light from a laser diode
(635 nm) or quartz halogen lampwas coupled into the waveguideand imaged with a CCD to assesstransmission. The scientists foundthat the efficiency of light confine-ment in the core liquid improvedwith an increase in total flow ratefrom 6 to 60 ml/hr. Higher flowrates help to reduce thermal diffu-sion across the channel’s widthand preserve the difference inrefractive index.
Liquid–liquid guidelets light flow
MICROFLUIDICS
The team tested its set-up (above) on a range of samplesincluding a low-density polystyrene with a hidden internaldefect (top). The image slices reveal the defect (bottom).
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3D negative refractionlenses trap particles
TECHNOLOGYR&D
METAMATERIALS
14 OLE • May 2006 • optics.org/ole
Three-dimensional negative re-fraction flat lenses (3DNRFL) areideal for electromagnetic trappingand manipulating of neutral par-ticles, according to Dennis Pratherand his research group from theUniversity of Delaware, US. Car-ried out at microwave frequencies,the team trapped a cluster of parti-cles and translated it 9.2 mmwithout moving the lens (OpticsExpress 14 2228).
“Using a full 3DNRFL, we havebeen able to demonstrate, for thefirst time, electromagnetic gradientforce trapping, similar to that ofoptical tweezers, but at microwavefrequencies,” say the authors. “The3DNRFL provides a unique mecha-nism to create a highly focused,strongly convergent beam inde-pendent of a single optical axis.”
Materials with a negative refrac-tive index essentially bend light inthe opposite direction to their con-ventional counterparts. Over thepast 12 months, several researchgroups have succeeded in fabricat-ing artificially engineered materials,which have a negative refractiveindex at optical frequencies.
Although this experiment wascarried out at microwave frequen-cies, the team believes that thetechnique can be adopted at opti-cal wavelengths. “In the opticalregime, the challenge lies in thefabrication of such a 3DNRFL,”say Prather’s team. “For opticalwavelengths, the flat lens would
become a thin patterned film,which would provide a focusedbeam with size limited only by thesize of the source.”
The flat lens used in this currentwork is a body-centred cubic pho-tonic crystal made from a low-lossmicrowave material. Negativerefraction is obtained by carefullyengineering the dispersion proper-ties of the photonic crystal, whichhas 20 layers in total each with athickness of 6.35 mm.
The team place the photoniccrystal lens 1 mm above a micro-wave monopole source emitting atbetween 16 and 17 GHz. On theother side of the lens, a first petridish is used to create a 10 mm airgap while a second contains thesample. A stereomicroscope that isequipped with a digital camerarecords the results.
The sample consists of polysty-rene particles that are dispersed ina liquid called dioxane. Mountedon a motorized stage, the mono-pole is translated and the teamfound that the cluster of trappedparticles follows the source andreforms at a new position. Usingthis approach, the researchersdragged the particles over 9.2 mm.
“The cluster size changes little asit moves over long distances,” saythe authors. “This is expected –because the flat lens has transla-tion symmetry for imaging and isdevoid of a unique optical axis. Asa result, there is no field curvatureand the quality of the monopoleimage is independent of its lateralposition. This is a very advanta-geous property for trapping as italso allows for effective manipula-tion without lens movement.”
SO U RC E S
Researchers from the ChineseAcademy of Sciences and HebeiUniversity, also in China, say that theyhave demonstrated the first passivelyQ-switched 946 nm laser to use agallium arsenide crystal as asaturable absorber. For a pumppower of 15W, the laser generated70ns pulses with an energy of3.76µJ at a repetition rate of 330kHz(Chinese Physics Letters 23 619).
“It should be noted that nodamage was observed on thegallium arsenide crystal during thewhole experiment,” say theresearchers. “With furtheroptimization of the galliumarsenide, higher average outputpower with better performancewould be obtained in the future.”
SE N S I N G
A two-photon laser-inducedfluorescence (LIF) technique tomonitor nitric oxide (NO) has beendeveloped in the US to study in-cylinder diesel combustion.According to the team from SandiaNational Labs and the University ofIllinois at Urbana-Champaign, thetwo-photon technique preventsmany of the problems associatedwith in-cylinder single-photon NOmeasurements (Applied Optics45 2089).
“The two-photon technique showsgreat promise for overcoming muchof the interference found whensingle-photon NO LIF techniques areapplied to engines,” say theresearch team. “Improvements arestill needed to increase signalstrength and to provide quantitativein-cylinder measurements.”
JOURNAL WATCH
The team’s lens is a photonic crystal with carefully engineered dispersion properties.
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TECHNOLOGYR&D/PATENTS
16 OLE • May 2006 • optics.org/ole
LICENSINGNovalux and Seiko Epson team upon microdisplay illuminationNovalux of the US has entered into a jointdevelopment and license agreement with SeikoEpson of Japan. The deal will see Novalux’sextended-cavity surface-emitting lasers (NECSELs)being used for RGB illumination in microdisplay-based products such as projection televisions.
Novalux will license its RGB laser referencedesign to Epson as well as supply the Japanesefirm with NECSEL semiconductor chips. Epsonhopes to develop optical engines for its 3LCDprojectors and expects to produce high-quality,high-performance projection displays with lowerproduction costs.
SETTLEMENTTokyo court rules on patent casebetween Chi Mei and SELThe Tokyo District court has ruled in favour of ChiMei Optoelectronics (CMO) in a patent disputebetween the Taiwanese firm and SemiconductorEnergy Labs (SEL) of Japan. SEL had brought the
patent infringement action involving SEL’selectrostatic discharge patent (JP3241708) foruse in LCDs against certain retailers whoseproduct used CMO’s LCD panels.
The court judged that CMO was not infringingSEL’s patent and also declared SEL’s patentinvalid. SEL was ordered to pay CMO ¥10 m(769 200) compensation for the commercialharm caused by SEL publicizing the infringementaction in the Japanese media. The court said thatSEL’s action constituted unfair competition andcommercial defamation, and ordered SEL to pay90% of the court costs for the case.
Ruling says Corning optical bio-sensor patent is fully enforceableThe United States Court for the District of Delawarehas ruled in favour of Corning in a patentinfringement suit between Corning and fellow USfirm SRU Biosystems. The court ruled that a patentexclusively licensed to Corning for opticalbiosensors was fully enforceable. The patent, US4,815,843, enables label-independent detectionof chemical, biochemical and biological
substances in a sample.The court added that Corning was entitled to a
permanent injunction against SRU Biosystems.Corning licensed the patent from Artificial SensingInstruments (ASI) of Switzerland and, inconjunction with ASI, filed the lawsuit in July 2003.
APPLICATIONPirelli details continuous opticalpreform to cable manufacturingPirelli of Italy has come up with a method formanufacturing optical cable in a single continuousprocess, starting directly from the optical preform.Detailed in patent application WO 2005/116712,the integrated manufacturing line includes adrawing assembly for the production of one ormore optical fibres from their respective preforms,plus a cabling assembly for producing opticalcable from the fibres. The cabling assemblycomprises a fibre buffering assembly that appliesa loose or tight coating to the fibres, and astrengthening and sheathing subassembly toapply one or more reinforcing and protective layersto the buffered optical fibres.
PATENTS
To search for recently published applications, visit http://www.wipo.int/pct/en/ and http://ep.espacenet.com.
By Belle DuméPhysicists in Denmark and France,led by Sergey Bozhevolnyi of theUniversity of Aalborg, have devel-oped a new class of waveguide thatcould get round one of the biggestobstacles to photonic circuits. Thedevices allow light at telecommu-nications wavelengths to be“squeezed” to below the diffractionlimit, allowing it to pass throughsmall regions such as channels ona chip (Nature 440 508).
At the crucial telecoms wave-length of 1.5 µm, light cannot passthrough the channels used toguide electrons in today’s siliconchips because they are too small.
One way to overcome this prob-lem is to use light waves to excite thecollective wavelike motions of bil-lions of electrons on the surface ofmetals. Unlike the light waves them-selves, these “surface plasmons” arenot restricted by the diffraction limit
of light. Bozhevolnyi and co-work-ers have previously shown that theplasmons can be used to guide lightthrough grooves in gold that aremuch narrower than the wave-length of the light used.
Now, the team has taken thiswork a step further by using chan-nel plasmon-polaritons – electro-magnetic waves that originate at
the interface of a metal and aninsulating dielectric such as air.
The researchers have shownthat these plasmons can guide andmanipulate light along the bottomof sub-wavelength V-shapedgrooves in a gold film without sig-nificant propagation losses. This isbecause the surface plasmonsremain tightly bound to the inter-
face and thus concentrate the lightinto a volume that is less than onewavelength across.
Channel plasmon-polaritonscan be used to transmit signals ofaround 1.5 µm. Furthermore, thepropagation length of a plasmonat a planar gold-air interface isaround 1 mm, which is longenough to optically connect twodevices on a chip.
“Our technique can already beused for many practical appli-cations, such as ultracompact opti-cal interconnects, interferometersand waveguide-ring resonators,”says Bozhevolnyi. “It should also beborne in mind that the channelplasmon-polaritons are bound to,and propagate along, the metal sur-face, thereby allowing for naturalintegration with electrical circuits.”
Belle Dumé is science writer atPhysicsWeb, http://physicsweb.org.
Surface plasmons squeeze lightCOMMUNICATION
Channel plasmon-polaritons intensity distribution in a waveguide-ring resonator witha diameter of 10 µm. Maximum transmission occurred at 1525 nm.
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Photomultiplier tubes are facing stiff competition from silicon-based low-light detectors.Jacqueline Hewett asks Joseph O’Keeffe, a founder of Irish firm SensL, why he believesthat silicon devices have what it takes to displace incumbent technologies.
Silicon detectors eye-upphotomultiplier markets
INTERVIEW
17OLE • May 2006 • optics.org/ole
SensL of Ireland believes strongly that its sil-icon-based low-light detectors have thepotential to displace alternatives such asphotomultiplier tubes (PMTs). Backing upthis confidence is the firm’s ability to pro-duce silicon photodiodes using CMOS-com-patible processing that are optimized forGeiger mode operation.
A closer look at the technology reveals cru-cial advantages such as low operating volt-ages, low cost, no excess light damage andpotential for integrated electronics. With asuite of products now available and morereleases on the cards, SensL could certainlybe a name to remember when it comes to vis-ible low-light detection and photon counting.
“Our core capability is making photo-diodes that are stable in Geiger mode and allthe associated silicon processing and optimaldevice geometries,” Joseph O’Keeffe, SensL’schief operating officer and companyfounder, told OLE. “We can keep the darkcount down and quantum efficiencies up forGeiger mode and photon counting.”
Although it has been in operation for justover two years, the company’s foundation is15 years of research into low-light detectionatthe Tyndall National Institute, which is partof the University College Cork, Ireland.
A quick browse through the company’swebsite and you will see that with a work-force of 18, SensL has turned academic suc-cess into commercially viable products,many of which it claims are world firsts.
This is largely thanks to the use of CMOS-compatible processing, which allows thefirm to make arrays of devices. Theapproach also allows read-out circuits to beintegrated onto the sensor and accessedthrough a USB interface.
The company also benefits from the Tyn-dall Institute’s silicon fab. “As part of our set-up agreement, we have access to the[Tyndall] foundry,” explained O’Keeffe.“This is extremely useful when you are try-ing to do quick and numerous iterations tofine tune different parameters. It gives us theability to turn around wafer runs in a matter
of weeks and customize structures to spe-cific applications.”
O’Keeffe explains that SensL is developingproducts under three different umbrellas,each of which is basically a different way ofexploiting its core technology. The first plat-form is what SensL calls its intelligent photoncounting module, the second is large-areahigh-gain avalanche photodiodes (APDs)and the third is a photon countingimager/array.
“In each case the building block is exactlythe same,” explained O’Keeffe. “The first plat-form uses one of our photodiodes, the secondis an array of photodiodes connectedtogether and the third is again an array but
here each pixel/photodiode is individuallyaddressable.”
Photon countingSensL’s range of photon counting modulesincludes its PCDMini, which it brands as theworld’s smallest photon counting moduleand as being ideal for OEMs, and the PCM-Plus, which it believes is the first USB photoncounting system.
“A typical photon counting architecturewould have a sensor, a counting card andsoftware to analyse the data,” said O’Keeffe.“But with our module, the counting is built-in. You can optimize parameters like biasvoltage and integration time through soft-
O’Keeffe (top left) believes that SensL’s SPMMini (bottom left) is a direct replacement for analogue PMTs.The product uses Geiger-mode photodiodes (top right) produced at Tyndall’s silicon fab (bottom right).
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ware. Most applications have one parameterthat is important and the user can go andoptimize for this.”
And it doesn’t stop there. The companysays that its PCSTime is the first integratedphoton timing system. With a high timingresolution (time stamping down to 2.5 ns),this product is said to be ideal for applicationssuch as time-correlated single photon count-ing and fluorescence decay.
Silicon photomultipliersSuch is the confidence in its silicon technol-ogy,SensL is branding its large-area high-gainAPDs as the first direct replacement for ana-logue PMTs. As O’Keeffe explains, low-lightdetection can be performed with a PMT or anAPD. While a PMT has a high, stable gain, itsdisadvantages include its bulky size, a highoperating voltage in the region of 1000V andits robustness. On the other hand, a siliconAPD is small and uses a low operating voltagebut its gain is limited to around 100.
“Our SPMMini product is what we call asilicon photomultiplier,” said O’Keeffe. “Ithas all of the advantages of silicon combinedwith the 106 gain of the PMT. The operatingvoltage is less than 100 V so this is a greatcombination of what silicon can do whilstcompeting with the gain of the PMT.”
SensL’s silicon photomultiplier is essen-tially an array of around 1000 of its photoncounting photodiodes connected in parallel.From a user’s point of view, the product stillhas a single active area. “It’s just that herethe active area is made up of many photo-diodes all packed together,” said O’Keeffe.
“Other important points are that you can-not overexpose the SPMMini whereas a nor-mal PMT will be damaged if you give it toomuch light,” continued O’Keeffe. “Thedevices are also insensitive to magnetic field,which is extremely important for a numberof applications such as nuclear medicine(PET and SPECT scans) and high-energyparticle detection.” SensL has high hopes forthese two “radiation detection” and othersecurity-based applications.
In addition, SensL is receiving interest fromfirms developing point-of-care instrumentswhere the advantages of the silicon photo-multiplier really begin to make a difference.
SensL also expects to see adoption into bio-medical fluorescence instrumentation in theshort term as the radiation detection appli-cations have a longer lead-time. That said,PMTs are used in an enormously wide rangeof applications and O’Keeffe is keen to stressthat anywhere a PMT is used, its devicescould be used instead.
The next release in this product platformwill be an array of APDs. “You could have1×32 or 1×64 for example,” said O’Keeffe.
“The technology allows you to have arrays ofhighly sensitive APDs, which you cannot dowith PMTs. We are planning to releasearrays in the coming months.”
The rest of 2006 will certainly be busy forSensL as it also hopes to release a photoncounting array (its third product platform)within the next six to nine months. “A bigaspect of the photon counting array is thatthere is nothing like that out there – it is anenabling technology,” explained O’Keeffe.“The first two platforms have a displacement
aspect because you could take out a PMT oran APD and put our product in its place.”
With several products on the market andmore in the pipeline, it now appears to bemake-or-break time for SensL. Will industryadopt its technology? Can SensL convincecustomers to replace PMTs with its siliconalternatives? These crucial questions resem-ble a “David and Goliath” battle but havinggot so far in such a short time, it’s hard to betagainst SensL making a success of its siliconknow-how.
INTERVIEW
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LIMO-LissotschenkoMikrooptik GmbHBookenburgweg 4-844319 Dortmund, Germany Phone: +49 (231) 22241-300Phone for US: +1 (404) 586 6860Phone for China: +86 (22) [email protected]
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OLEMayAdverts20 24/4/06 10.45 am Page 1
A femtosecond laser’s ability to generate an intense electric field makes it ideal fordisrupting missiles that use infrared guidance systems. Emmanuel Marquis describes aground-based solution that could protect civilian and military aircraft against missile attacks.
Ultrafast pulses foolheat-seeking missiles
DEFENCE
21OLE • May 2006 • optics.org/ole
Shoulder-fired ground-to-air guided missilesknown as MANPADS (man-portable airdefence systems) have been widely used inconflicts around the globe since the 1960s.They account for a large number of aircraftdowned in recent wars and now pose a majorthreat to military and civilian transport alike.
Such missiles are usually short-rangedevices, with engagement distances close to3000 m, and operate on the principle ofinfrared detection. The first generation thatappeared in the 1960s, such as the Soviet SA-7 MANPAD, used a cooled infrared detectoroperating in the 1–5 µm range to home-in onthe hot jet plume of the aircraft engines.
New generations, such as the US Stinger,combine infrared and ultraviolet imagingdetectors making them substantially harderto jam as they can lock on to lower heat gener-ation sources, such as aircraft landing lights.
Civilian aircraft at low altitude makingtheir final approach into airports are virtu-ally defenceless targets against MANPADSand may not survive a direct hit to an engineor fuel tank. Although various techniqueshave been investigated to enhance the pro-tection of aircraft against this threat, noneare currently satisfactory.
For example, the lower exhaust gas tem-perature of double-flux civilian engines mayprevent some earlier generation missilesfrom locking on as the infrared emissivity islow compared with military engines. Whena civilian aircraft is landing and there is noengine thrust, the exhaust gas temperaturefalls below 400 °C. However, the aircraft willbe a target during the take-off phase whenthe engines are providing maximum thrust.In addition, transport aircraft carrying a fullload of passengers and fuel are not allowed toperform evasive manoeuvres.
Another way to improve protectionagainst MANPADs is through flare car-tridges, which can be mounted on some VIPor head-of-states transport aircraft, but thereis a question mark over the fire risk associ-ated with this approach. The transport air-
craft can be on a parking lot in close proxim-ity to a refuelling aircraft and the high tem-perature of the cartridges creates the risk ofstarting a fire accidentally.
Onboard laser jammers, similar to the onesused on military platforms, can be mountedon civilian jetliners. These systems haveshown reasonable efficiency but have highmaintenance and operation costs. At present,no commercial airline company has suffi-cient operational margin to afford this option.
Ground-based high-power microwavesources are also a feasible solution but thisraises huge questions over electromagneticcompatibility. It may kill the missile, but whatif it also kills the aircraft electronics? Such
microwave systems are suitable if you fly a1965 Boeing 707 but definitively not on afly-by-wire recent platform.
Femtosecond solutionAll of these reasons have motivated the studyof a ground-based solution that takes advan-tage of the properties of femtosecond lasers.A good solution has to be ground-based forcost reasons, has to damage the missile withminimal side effects and avoid residues fromfalling from the sky. The ability to jam a mis-sile and make it fly in a pre-determined areais an ideal solution.
Femtosecond lasers emit pulses that reachtremendously high peak powers and moder-
ground-basedlaser jammer
protectedairspace
terminal building
runway
runway
protectedairspace
Ground-to-air guided missles (top left) are a threat to civilian and military aircraft. Femtosecond lasers,such as the one top right, create intense electric fields that can disrupt the missile’s guidance system.Positioning such lasers at the ends of a runway can protect departing and arriving aircraft (bottom).
US
Dep
artm
ent
of D
efen
se
THAL
ES L
aser
THAL
ES L
aser
OLEMayTHALES21-23 24/4/06 10.31 am Page 21
ate energies. Such ultrafast pulsed lasersexhibit a very interesting effect: even at lowenergy operation, the electric field generatedat the focal spot of the beam reaches highlevels. For example, 100 mJ, 100 fs pulsesgenerate a peak power of 1 TW and an elec-tric field in excess of hundreds of megavoltsin the focal spot.
When propagating in the air, such laserbeams create filaments of plasma that canpropagate over large distances, which areideal for disrupting a missile’s infrared guid-ance system. If this sort of beam is directedtowards a missile guidance system, it will cre-ate several desirable effects. Firstly, theintense electric field will damage the missile’soptics through an avalanche ionizationeffect and will cause the optical material tobreak down. Secondly, the electric field willionize the surrounding air and block the mis-sile’s field-of-view. Finally, the plasma gener-ated in the air acts as a flare for the missile’sinfrared sensor.
How to protect an airportOur airport protection concept relies ontruck-mounted lasers that are deployed onthe extremities of each runway to safe-guard departing and arriving aircraft. Eachtruck is equipped with a femtosecond laser
and a rotary turret to cover the appropriateangular sector.
For example, the laser would be a chirped-pulse amplification system based on a Ti:sap-phire lasing media, with a repetition rate of10 or 100 Hz. Several terawatts of peakpower at 800 nm are required for efficientlong filament production in the air and thelaser has to be equipped with a spectralphase-shaper to provide air propagation dis-persion compensation.
Such laser jammers can be spread every5–10 km on the ground to protect a com-plete access corridor and as they are truck-mounted, reconfiguration of the protectedairspace is quite easy.
The system has two modes of operation. Inpreventive mode, the laser is permanently fir-ing and protects a pre-determined zone in theairspace. A simple example would be to createa plasma shield below the aircraft’s flight path.There is also the option to change the trajec-tory of the plasma and divert the missile.
In defensive mode, the laser is on standbyand is triggered by a missile launch detector.Such an alert would also give the coordinatesof the launch point allowing the laser to befired into the missile’s estimated trajectory.The missile launch detector is either a classi-cal rocket plume optical detector or a
microwave Doppler radar system that leadsto a much better false alarm rate.
Practical alternativeThis solution is suitable for protecting civil-ian airports as well as military installationsand has several key advantages. The jam-ming concept is ground-based, mobile, andrequires only a moderate power source. It is apractical alternative to aircraft-mountedlaser jammers – a solution that no commer-cial airline can afford today.
It also benefits from the inherent proper-ties of femtosecond lasers that effectivelydamage the optics used in the missile and dis-rupt its guidance system. The ground-basedlaser jammer can effectively tow the missileaway from the airport area. Not only can thesystem be activated very quickly and jammissiles with a short time-of-flight, it alsoproduces no chemical or mechanical waste.
With a flash of light in the air and the soundof thunder, terrorist-launched MANPADS canbe successfully diverted from their targets.
Emmanuel Marquis is vice-president ofdevelopment at THALES Laser in France. For moreinformation about this project e-mail [email protected] or visit thecompany’s website, www.thales-laser.com.
DEFENCE
23OLE • May 2006 • optics.org/ole
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Adlares, E.ON Ruhrgas and the German Aerospace Centre(DLR) think that their airborne LIDAR system could help torevolutionize gas pipeline monitoring, increasing networkinspection rates from 2 to 80 km/h. James Tyrrell catchesup with Adlares’ Matthias Ulbricht to find out more.
Helicopter LIDAR speedsREMOTE SENSING
24 OLE • May 2006 • optics.org/ole
Gas pipeline inspection is a huge task. Justlooking at the figures for Germany alone,with a network of more than 40 000 km oflong-distance gas transport pipelines, theneed for a fast and remote monitoring systemsoon becomes apparent. If you then considerthe many transit pipelines running throughthe country from Eastern Europe into France,Belgium and Holland, and the various metro-politan gas distribution networks, you beginto identify a real market opportunity.
Currently, gas companies such as E.ONRuhrgas, with a network of approxi-mately12 000 km, rely on monthly airbornevisual inspections backed up by walking sur-veys. The two-person walking teams ensurea high level of pipeline safety, but withinspection speeds of just 2 km/h, it is anexpensive task for the industry.
The ideal solution of course would be tocombine a remote sensing technique withthe routine aerial surveillance. However, forthe system to be attractive to gas companies,the apparatus must be able to detect tiny gasleaks of just 100–150 l/h, which makes theexercise much more complicated.
Getting started Undeterred by the difficulty of high-speedpipeline inspection, Adlares, a four-personcompany located in Berlin, Germany, wasfounded in 2001 to develop mobile LIDAR sys-tems for methane monitoring. Facing anincreasingly competitive market, gas firmswere anxious to get their hands on the tech-nology. Adlares co-founder, Matthias Ulbricht,was well-equipped for the task as he was previ-ously general manager of Berlin-based ElightLaser Systems, a developer of LIDAR instru-ments for air pollution monitoring.
“What counts is the cost per kilometreand [with our airborne LIDAR system] wecan offer not just better prices, but also ahigher density of measurement points,”Ulbricht told OLE. “The figures are stillunder discussion as it depends on the size ofthe network, but there will be sufficient sav-ings for the gas companies.”
Dubbed CHARM (CH4 airborne remotemonitor), the gas-sensing programme is ajoint effort between Adlares, the DLR andE.ON Ruhrgas. Energy firm E.ON Ruhrgasprovided project funding and DLR staff inOberpfaffenhofen and Stuttgart suppliedexpertise in atmospheric physics togetherwith a wealth of knowledge in laser anddetection systems.
Absorption spectrumOne of the key technical decisions facing theCHARM scientists was the choice of operat-ing wavelength. “When you look at theabsorption spectrum of methane you seethat it has four major absorption bands,”Ulbricht explained. “From the point of viewof the available technology, 1.6 µm is themost appealing region – you have fast detec-tors, the optical materials are standard andyou can build OPOs [optical parametric oscil-lators] with sufficient output.”
However, the requirement to detect verysmall leaks forced the designers from the DLRto consider other factors. “The problem with1.6 µm is that the absorption cross-section ofmethane is fairly low,” said Ulbricht. “Movingup to the 2.4 µm region doesn’t give you anymajor benefits in terms of sensitivity, but itdoes make the technology more complicated.At 7.8 µm, methane is hard to detect becauseof the interference with other gases.”
With its focus on device sensitivity, thegroup decided to take advantage of the strongabsorption band around 3.3µm and in returnwas forced to develop custom hardware.
Customized LIDARAt the heart of the system is a two pulse dif-ferential LIDAR set-up. A seeded Nd:YAGlaser emitting at 1064 nm feeds its 100 Hzdual pulse output (15 mJ/pulse) into a cus-tom OPO, which is operated in ring cavitymode and emits in the 3 µm region. The needfor mobile operation placed certain con-straints on CHARM’s engineering team.
“Diode pumping was mandatory for usbecause we have limited electrical power on
the helicopter,” said Ulbricht. “If you have alamp pumped [device], the total efficiency ismuch lower.” According to Ulbricht, the finaloutput energy of 0.8–0.9 mJ/pulse is suffi-cient to collect high-quality data.
“We developed the apparatus in such away so that we can make a single pulse pairevaluation,” he revealed. “We transmit twolaser pulses, the first pulse is tuned preciselyon a methane absorption line in the 3 µmregion and the second pulse is tuned close-byto the absorption line.”
Both probe and reference pulses are sentfrom the helicopter, which typically flies at analtitude of 120 m. The expanded beam trav-els through the atmosphere towards theburied pipeline and is fully eyesafe on theground. A small fraction of the laser light isthen scattered back to the system where it iscollected by a telescope coupled to a fast ana-
Airborne LIDAR: the GPS-equipped CHARM unit fits neatly into a BO1
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OLEMayLIDAR24-25 24/4/06 10.42 am Page 24
logue detector. Finally, the signal is digitized,ready for analysis.
“As long as we have no methane in the air,both laser pulses will behave similarly, whichmeans that the back scatter intensity will bethe same for both laser pulses,” Ulbrichtexplained. “We measure the laser power ofeach spot so that we can normalize the sig-nals and a methane reference cell ensuresthat the probe beam is tuned exactly to theright wavelength.”
If methane is present in the beam path,then the first laser pulse is slightly attenu-ated as the gas molecules absorb theinfrared light.
In practise, the system computes a ratio ofthe two signals, correcting for the differencein absorption cross-section and the opticalpath length to determine the correspondingmethane concentration.
Field trialsWorking with a benchtop set-up, the first taskfor the airborne LIDAR team was to test itsapparatus on the ground. “We started withfield trials where we measured out of the win-dow and looked at a target 150m away just tosee if it was possible to detect methane,” saidUlbricht. “Then we switched to a small heli-copter, a so-called MD500, and made our firstflights over artificial leaks. We opened gasbottles slightly and again were able to suc-cessfully detect the methane.” Today, the sys-tem is flown in a BO105 helicopter, whichgives the option of longer flight times.
Initially, the team attempted to guide itsLIDAR unit manually, steering the beam viaa joystick to follow a video-camera image ofthe pipeline. However, this required a highlevel of operator skill and was felt to be unsat-isfactory for routine inspection. In 2004, the
group began to devise an automatic beam-guiding system based on a rotating mirrorand position-sensing electronics.
“We have developed and patented a scan-ner that distributes the measurement pointsnot only precisely on the pipeline, but alsoalong either side of it,” said Ulbricht. “Thismeans that even if the leak comes out of theground, say 2 m away from the pipeline, wecan still identify it.” The beam-guiding sys-tem is also useful when the helicopter isunable to fly directly over the pipeline.
Thanks to the unit’s inertial measurementcapability, the scanner compensates for leftand right (roll) movement along the heli-copter’s flight axis. As Ulbricht explains,uncorrected roll movements are more dis-ruptive to the scan profile than front andback (pitch) deviations from the flight path.
The set-up is fitted with a differential GPS,which gives a positioning accuracy of betterthan 50 cm, and linked up to a computerdatabank of gas pipelines. With the newlyautomated apparatus, the operator simplyhas to select the pipeline on-screen and thenthe scanning system will do the rest. Accord-ing to Ulbricht, the precision for pinpointingthe laser is now better than 2 m.
However, there is more to the set-up thanjust pinpoint accuracy. Adlares has alsodeveloped a suite of “intelligent” data algo-rithms that can distinguish between genuineand false gas alerts – methane is naturallypresent in the atmosphere at levels of1.7–2 ppm. The software can also compen-sate for other methane sources in the areasuch as waste disposal sites.
Stamp of approvalWith the system now very much up and run-ning, the CHARM team is busy gaining expe-rience on a real gas pipeline and has startedevaluating the E.ON Ruhrgas network. Infact, the plan is to monitor the entire pipelinetwice this year.
Meanwhile, the German gas and waterassociation is evaluating the group’s LIDARmethod against its gas inspection norms toconfirm that the airborne measurement canbe used officially in place of a walking survey.In terms of air safety, the German FederalAviation Authority is expected to formallyapprove the technique later this year.
The company presented this work at Laser OptikBerlin, which took place in Germany on 23–24 March.
25OLE • May 2006 • optics.org/ole
ds up pipeline inspection
o a BO105 helicopter and can be pre-loaded with pipeline coordinates to fully automate the gas monitoring process.
OLEMayLIDAR24-25 24/4/06 10.43 am Page 25
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Slowing down light to produce optical delay lines for communication networks has advancedenormously in the last year. Luc Thévenaz and Miguel Gonzalez-Herraez chart thisrecent progress and describe the new challenges facing developers of practical devices.
Slowing light in opticalfibres sees fast progress
OPTICAL COMMUNICATION
27OLE • May 2006 • optics.org/ole
The ability to temporarily store a signal andrecall it at an exact point in time is an essen-tial function of any type of signal processingsystem. The development of all-optical signalprocessing has been seriously impaired dueto the lack of timing tools. But as we advancetowards all-optical systems, this situationmust improve if we are to avoid bottlenecksin data transmission and routing.
The main motivation behind this line ofresearch is the development of all-opticaldelay lines, buffers and routers as well as all-optical memory chips. Such devices couldhave important consequences for opticaltelecommunication and computer net-works. If the complex functions of timingand routing could be performed all-optically,this would drastically boost performance andbridge the first gap towards all-optical logicfunctions and computation.
The active control of the speed of a lightsignal to generate tuneable delays offersnumerous benefits and has attracted muchattention. Research teams globally are striv-ing to develop fast-access memories and opti-cally controlled delay lines compatible withoptical computing and fibre-optic communi-cation systems.
There have been many reports of success-ful ways to control the group velocity of lightranging from slowing light to a near stopright through to producing a group velocityexceeding the vacuum velocity of light.
All of these fundamental experimentswere based on the concept of “slow and fastlight”, which relies on a specific propertyobserved in all narrow spectral resonances.Here, a sharp spectral change in themedium’s transmission results in a steep lin-ear variation of the effective refractive indexwith wavelength. This in turn results in astrong group velocity change at the exactcentre of the resonance.
This effect turns out to be the strongestfor the narrowest spectral resonances. Forthis fundamental reason, early experimentswere all carried out in exotic media such asultra-cold atomic gases or atomic transi-
tions in crystalline solids working at well-defined wavelengths.
Until last year, there was no knownmethod for realizing optically controlleddelays in optical fibres. The major difficultywas generating narrow spectral resonancesin a highly disordered material such as glass.
Things changed in January 2005 whenour team at Ecole Polytechnique Fédérale deLausanne in Switzerland discovered that anefficient nonlinear effect seen in silica, calledstimulated Brillouin scattering (SBS), cangenerate the narrow resonances needed toproduce large, observable delays (OpticsExpress 13 82). In the same paper, we exper-imentally achieved a tuneable delay of 30 nson a 100 ns optical pulse.
Encouragingly, these results were quicklyindependently replicated by others followingthe same approach. Throughout 2005, sev-eral groups demonstrated different schemesfor performing all-optical delaying in opticalfibres using Raman-assisted parametricamplification, wavelength conversion associ-ated to a dispersive propagation and Ramanamplification. All of these techniques tried toimprove the delaying performance, in termsof bandwidth and maximum normalized
delay (delay divided by the pulse temporalwidth). A similar approach was taken toimplement compact temporary optical stor-age on integrated optical chips.
Stimulated Brillouin scatteringSBS can substantially modify the velocity ofan optical pulse. The phenomenon itselfresults from the interaction between twooptical waves and an acoustic wave in amedium. The effect is very efficient in opticalfibres and can be observed using moderatepowers in the mW range. As the name sug-gests, the effect can also be stimulated so thatthe scattered optical wave sustains and feedsthe scattering acoustic wave.
SBS is traditionally observed in opticalfibres by propagating an intense coherentwave called a “pump” in one direction and byobserving the amplitude growth of a weakcoherent “probe” wave propagating in theopposite direction along the optical fibre.
If the pump and probe waves have a smallbut finite frequency difference, their superpo-sition produces a longitudinal fringe patternthat moves along the fibre at a velocity relatedto the frequency difference, wavelength andthe refractive index of the fibre medium.
There are still challenges to overcome before the lab-based set-ups can be turned into practical devices.
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OLEMaySLOWLIGHT27-29 21/4/06 3.49 pm Page 27
This moving periodic intensity patterngives rise to a compression wave as a result ofelectrostriction. For an exact frequency dif-ference, the velocity of the pattern matchesthe acoustic speed in the medium and thecompression wave turns into a sustainedacoustic wave.
In the low-loss window of optical fibresand at the crucial telecoms wavelength of1550 nm, the pump and probe waves mustbe separated in frequency by approximately10 to 11 GHz. The resulting compressionwave induces a refractive index change thatis similar to a moving Bragg grating.
Such a grating is exactly phase-matched tocouple light from the higher frequency waveto the lower frequency wave. If the probewave has a lower frequency than the pump,it will gain amplitude from the pump andgrow, provided that the frequency differenceexactly matches the condition for a sustainedacoustic wave. If the probe has a higher fre-quency it will experience a narrowband loss.
Exploiting SBS in optical fibres is an idealway to generate a narrowband gain or loss atany wavelength and with a strength deter-mined by the pump power. For example,these resonances can be produced for any ofthe channels within a wavelength divisionmultiplexing transmission system.
Slow light and practical devicesIn any sharp spectral transition, a refractiveindex change is associated with this gain/lossprocess and a substantial change of the group
index can be observed, as shown in figure 1.This index determines the velocity of the sig-nal envelope and can be substantially modi-fied within a very sharp spectral transition.
For a gain process, the group index increasesresulting in slow light. Conversely, a loss resultsin fast light. In the latter case, extreme situa-tions may lead to a group index of less thanone where the signal envelope propagatesfaster than the vacuum velocity of light oreven at a negative group velocity. A negativegroup velocity means that the peak of thepulse actually exits the fibre before entering it.
This rather weird situation can beachieved thanks to a severe pulse distortion.This was experimentally and strikinglydemonstrated in optical fibres by our team(Applied Physics Letters 87 081113) and isrepresented in figure 2.
In the same paper, we demonstrate howthe group velocity can be reduced to one-third of its normal value in optical fibres. AtOFC2006, which was held in Anaheim, US,in March, a postdeadline paper fromSouthampton University, UK, detailed a four-fold speed reduction in a bismuth-oxidehighly nonlinear fibre.
From the point of view of practicality, therelevant quantity is not the change inducedin the group velocity of the medium, butrather the amount of fractional delay (i.e. thedelay divided by the pulse length) achieved inthe medium.
In an Optics Letters paper in July 2005, ourgroup unveiled a way to achieve large frac-tional delays by simply cascading delayingfibre segments and inserting unidirectional
OPTICAL COMMUNICATION
28 OLE • May 2006 • optics.org/ole
delay advancement
ng = n+v . dndv
gain
n
ng
v0–vB vo v0+vB
Kramers–Kronigrelations
0
–50
5
10
15
20
0 50time (ns)
puls
e am
plitu
de, a
.u.
–12 dB
0dB
21 dB
–6 4 8position (m)
0 dB –12 dB
peak to peak ~3 m
fibre(2 m)
–4 –2 0 2 6
Fig. 2: measured pulse delay and advancement experienced by a light pulse propagating through a 2 mfibre for different gain or loss induced by stimulated Brillouin scattering. The inset compares therespective positions on a distance scale of the pulse propagating in normal conditions and of the mostadvanced pulse, demonstrating that in this case the pulse peak exits the fibre before entering it. Thissituation corresponds to a negative group velocity. The fibre length is represented by the shaded area.
Fig. 1: relations among gain, refractive index andgroup index in Brillouin slow light. When a pumpwave at frequency νo propagates in the fibre, a probewave propagating in the opposite directionexperiences a narrowband gain if its frequency isνo–∆ν and a narrowband loss if its frequency isνo+∆ν. The associated refractive index changestrongly modifies the group index and thus the signalvelocity at the centre of the gain/loss spectral line.
OLEMaySLOWLIGHT27-29 21/4/06 3.50 pm Page 28
attenuators to compensate for the large sig-nal amplification.
A maximum delay of 152 ns was recordedusing four cascaded segments, which corre-sponds to 3.6 times the initial pulse width.This remains the largest fractional delayobtained to date in an optical fibre, but largervalues can undoubtedly be obtained byappending more delaying segments.
New challenges are now emerging to turnthese so-called all-optical delay lines intopractical devices. One factor is that the band-width is limited to the characteristic band-width of the Brillouin scattering, which isaround 25 MHz in conventional singlemodeoptical fibres. Also, for a modest fractionaldelay of one pulse length, the power of thesignal is amplified by a factor of 1000.
New techniques are being proposed toovercome these problems. For example, werecently outlined a simple scheme to over-come the bandwidth problem in Brillouinslow light (OLE April 2006 p11). The gainspectrum seen by the signal is given by theconvolution of the pump spectrum with thecharacteristic gain spectrum of the Brillouingain process. If the pump is broadened, theBrillouin gain process is also broadened andthe slow light bandwidth is improved. Usingthis method, we can achieve GHz-bandwidthslow light by simply adding noise to the elec-trical input of the pump laser.
Daniel Gauthier and his team from DukeUniversity, US, have pushed this method tothe limit and reported 12 GHz-bandwidthslow light in a postdeadline paper atOFC2006. Crucially, this makes the delayline compatible with today’s 10 GB/s trans-mission systems.
Several issues still need to be resolved beforethe advent of practical devices, most impor-tantly realizing tuneable delays that do notamplify the signal by the 30dB currently seenfor one pulse width delay. The signal changemust be practically maintained for any delayto make it compatible with bistable devices.
Another potential application is the all-optical buffer, which requires fractionaldelays much larger than those obtained sofar, up to 1000 pulse widths. This means theentire data packet can be buffered and prop-erly reordered in time.
This research topic will certainly remainvery active in the coming years and musttake up the challenge to shift from pure sci-ence to engineering in order to succeed.
Luc Thévenaz is the head of the Optical ProcessingGroup at Swiss Federal Institute of Technology inLausanne, Switzerland. Miguel Gonzalez-Herraezis assistant professor at the University of Alcalá-Madrid, Spain. For more information, [email protected] or [email protected].
OPTICAL COMMUNICATION
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A new method of phase and amplitude control delivers near-transform limited pulses,even after passing through complex beam delivery systems such as multiphotonexcitation microscopes. Steve Butcher and colleagues from Coherent explain.
Multiphoton approachshapes ultrafast pulses
PULSE SHAPING
31OLE • May 2006 • optics.org/ole
Ultrafast laser pulses present unique chal-lenges and offer unique opportunities tostudy structures and processes in biology,physics and photochemistry. As femtosecondpulsewidths are pushed to ever shorter dura-tions, the performance of the laser systemand the overall experiment are often limitedby subtle phase and amplitude effects.
Phase errors arise from group velocity dis-persion (GVD) induced by virtually everyoptic within the laser and beam delivery sys-tem. Until recently, commercial and user-built tools to counteract these phase delayshave been cumbersome to implement and/orlimited in their scope of success. Now, aclosed-loop method provides complete turn-key control of pulse phase over the entirespectral bandwidth of any ultrafast laser.
This turnkey method can easily be used tocorrect phase effects from an entire experi-mental system – including downstream beamdelivery optics such as those found in multi-photon excitation (MPE) microscopes. Thesame pulse measurement and shaping tech-nology can be configured to arbitrarily shapethe pulse’s amplitude in order to correct forgain narrowing or gain saturation, to producea shorter transform limit, or to select or blockspecific wavelength segments. This pulse con-trol method can also be used to produce cus-tom temporal shapes, including double pulses.
The transform limit and GVDIn a mode-locked Ti:sapphire laser oscillator,interference between the longitudinal cavitymodes yields a single pulse circulating in thelaser cavity. When there is no phase delaybetween the modes, the result is a so-calledtransform-limited pulsewidth. Spectralbandwidth and temporal pulsewidth arerelated through a Fourier transform: a widerspectral bandwidth gives more longitudinalmodes that interfere and result in a shortertransform limit (see figure 1).
But in real world ultrafast laser systems,this transform limit is rarely reached. Even ifit is reached within the laser, the pulse ischirped (stretched) to some degree by subse-
quent beam delivery optics before it reachesthe interaction zone of the experiment as aresult of GVD.
GVD refers to the fact that the velocity of
light in any medium is a function of wave-length. Materials such as glass lenses, multi-layer optical coatings and laser crystals areall dispersive and can impart significantGVD. Most of these materials exhibit positivedispersion where longer wavelengths travelat a higher velocity than shorter wave-lengths. For this reason, a high-performancelaser oscillator contains some form of opticalarrangement that provides negative disper-sion in an attempt to counteract intracavityGVD effects.
The problem can be even more complex ina system that includes an amplifier. Here, theoscillator pulse is deliberately chirped byorders of magnitude before it is injected intothe amplifier. This avoids high peak-powersthat could damage the optics inside of theamplifier. The amplified exit pulse is then re-compressed. Both the stretcher and the com-pressor usually consist of a pair of matcheddiffraction gratings. In principle, the com-pressor perfectly restores the original shapeof the pulse. However, in practice, undesir-able phase (and amplitude) modificationscan occur within the amplifier, where everyoptic imparts its own specific dispersion pro-file to the pulse. The end result is that thegroup velocity delay can have a complex,nonlinear dependence on wavelength.
An amplifier can also affect the amplitude(spectral profile) of an ultrafast pulse due togain narrowing or gain saturation. Gain nar-rowing occurs because the amplifier gain ispeaked at its centre wavelength. Every timethe pulse passes through the Ti:sapphire crys-tal, the centre is amplified more than thewings of the pulse, making it successivelynarrower. In addition to modifying the spec-tral profile, gain narrowing lengthens thepulsewidth that is obtained after re-compres-sion, because of the transform relationshipbetween spectral bandwidth and pulsewidth.
Controlling phase with an SLMThe ideal phase correction tool would be aflexible, programmable method that adjustsphase as a function of wavelength. This can
2Lc
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Fig. 1: in a mode-locked laser, the fixed phaserelationship between the continuous-wave cavitymodes gives rise to interference that causes thesemodes to collapse to a single pulse circulatingaround the laser cavity. If this phase relationship iscompromised, this leads directly to a pulsewdiththat is longer than the transform limit.
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PULSE SHAPING
32 OLE • May 2006 • optics.org/ole
be accomplished by using a programmablephase mask in conjunction with a zero dis-persion stretcher. This type of stretcher later-ally spreads the pulse as a function ofwavelength and then recombines it in a waythat does not chirp the pulse. In the middle ofthe stretcher, at the so-called Fourier plane,the beam is parallel (collimated) with a linearmapping of wavelength to lateral displace-ment (see figure 2).
A linear liquid crystal array, often called aspatial light modulator (SLM), can then beused as a programmable phase mask at thislocation. Increasing the voltage at any of theSLM pixels retards the phase of light passingthrough that pixel. For an array with 128pixels, the spectral bandwidth of the laserpulse is divided into 128 equal segments andthe phase of each of these wavelength seg-ments can be arbitrarily changed by adjust-ing the voltage to that pixel. This type ofphase correction tool is normally insertedbetween the oscillator and the amplifier, sothat any losses it introduces have minimaleffects on the final system power.
This approach can provide a flexible andrigorous correction of phase distortion but itis potentially very difficult to implement as128 different voltage values are required. Inprinciple it is possible to use a pulse diagnos-
tic instrument such as a FROG (FrequencyResolved Optical Gating) or SPIDER (SpectralPhase Interferometry for Direct Electric-fieldReconstruction) to first measure the phasecharacteristics of the pulse as a function ofwavelength. These parameters are then usedto calculate phase correction parametersand then actual voltage values for the liquidcrystal array.
But even for a skilled laser operator famil-iar with these calculations, this processwould require two or three manual iterationsto get an optimum result: a compressed pulseat < 1.1 times the transform limit. While rig-
orous and successful, this is not a solutionthat could be widely used.
Integrated MIIPSFortunately, a new method of phase andamplitude characterization has been devel-oped that has led to an integrated, turnkeypulse measurement and correction solutionbased on a liquid crystal array. This method,pioneered by Marcos Dantus and co-workersat Michigan State University, US, uses ameasurement tool called MIIPS (Multipho-ton Intrapulse Interference Phase Scan).Using this approach, the researchers have
Fourier plane(SLM location)
outgoing lightincoming light
dispersingelement
collimatingoptics
Fig. 2: in a zero-dispersion pulse stretcher, a grating spreads the pulse laterally at the so-called Fourierplane. At this location wavelength maps linearly with X-axis location.
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demonstrated pulses of less than 1.001times the transform limit.
The basic principles of MIIPS are fairlystraightforward. Importantly, MIIPS is a sin-gle beam technique that does not require aninterferometer. Instead, it uses the alreadydescribed liquid crystal phase maskapproach to impose a known (reference)phase delay function on the laterally dis-persed ultrafast beam. The overall phasedelay of the beam as a function of wave-length is a combination of the existing phasedelay due to the laser optics and this appliedreference function.
The re-compressed beam is then sampledusing a beamsplitter or mirror and directedinto a thin nonlinear crystal designed for sec-ond harmonic generation (SHG). In practicea 0.05 mm-thick beta barium borate crystalis used to enable broadband phase matching.This is followed by a spectrometer and CCDdetector that measures the SHG intensity asa function of wavelength. This approachyields second derivative data about the spec-tral phase, which is then integrated by thesoftware to retrieve the original spectralphase of the beam.
Coherent has now exclusively licensed thistechnology and will launch a turnkey phasecontrol system based on this approach atCLEO 2006 in Long Beach, California, US.This new product, called Silhouette, consistsof the phase correction box and a separatefibre-coupled detector.
The integrated correction box contains a
low-loss, adjustable bandwidth stretcherand the liquid crystal SLM. The compactdetector head contains the thin SHG crystal,which is then fibre-coupled to a spectrome-ter. System software and a dedicated laptopcontroller automatically acquire the SHGintensity readings and iteratively adjust theliquid crystal voltages to create the desiredphase profile across the laser’s spectralbandwidth. The uncorrected and correctedphase information can also be directlyaccessed by the operator.
For researchers who also want amplitudecontrol as a function of wavelength, a secondversion will be available in which the singleLCD array is replaced with a double arraythat incorporates a polarizer. Here, each ofthe 128 elements can also act as a variableamplitude attenuator. The transmittedintensity is controlled by the voltage to thetwo LCD arrays.
In most instances, the optimum locationfor the pulse shaping system will be betweenthe oscillator and amplifier (see figure 3). Butthe fibre-coupled detector head means that itcan be inserted at any arbitrary location inthe laser system or delivery optics, and thephase and/or amplitude will be re-shaped atthat point. In applications where the pulsecharacteristics of the experimental set-upmay change with time, for example in apoorly temperature-controlled environment,the system can re-sample the phase and/oramplitude and quickly make any necessarycorrections.
This approach will allow laser operatorswith limited expertise to take even a poorlycorrected ultrafast laser set-up and do twothings. First, phase errors can be corrected toachieve a transform-limited pulse. Second,the spectral profile can be broadened so thatthis transform limit is even shorter than ispossible without pulse-shaping.
For more sophisticated users, the systemprovides complete access to the uncorrectedand corrected phase and amplitude infor-mation. In addition, this system can be usedto arbitrarily modify the phase and ampli-tude profile of ultrafast pulses to createsome other interesting possibilities. Thisincludes the ability to switch the wave-length of a broadband pulse to selectivelyexcite one of the multiple fluorophores in aMPE microscope. The user can also create adouble pulse profile with the pulse pairclosely spaced in time, for coherent studieson fast processes such as wave packet evo-lution in real-time molecular dynamics. Fortelecom applications the pulse-shaperenables the generation of a multiwave-length spectrum for WDM or high repeti-tion rate pulse bursts for OTDM.
ConclusionUltrafast laser builders and users have longstruggled to obtain the elusive transform-limited output pulse with varying degrees ofsuccess. Even with highly corrected systemsthat approach (i.e. < 1.5 times) the trans-form limit, the downstream beam deliveryoptics generally stretch the pulse.
A new integrated approach based onMIIPS allows any commercial or user-builtlaser system to be interrogated and modifiedat any point within the entire experimentalset-up, including at the focus of an MPEmicroscope. What’s more, the same tool canbe used to programme subtle effects into thebeam for novel ultrafast experiments.
The authors of this article are Steve Butcher, BojanResan, Alan Fry and John MacKay of Coherent,Inc. Steve Butcher is a senior product manager atCoherent. For more information about the newSilhouette product e-mail [email protected] or see www.coherent.com.
PULSE SHAPING
33OLE • May 2006 • optics.org/ole
Ti:sapphireoscillator
pulse shaper amplifier
beam deliveryoptics
microscopeoptics
detector head
sample
fibre-optic for remotepulse sensing
Fig. 3: an integrated approach with a remote fibre-coupled SHG sensor head, enables phase and/oramplitude correction wherever this head is used to sample the ultrafast pulse.
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Selecting the right mirror for the right job is no trivial task. However, help is at hand asMichael Case and Mark Dykstra guide OLE readers through the process.
Robust mirrors take ondemanding applications
PRODUCT GUIDE
34 OLE • May 2006 • optics.org/ole
Ultraviolet (UV), visible (VIS) and infrared(IR) applications all have something in com-mon; they require optics to control, shape,split, filter, attenuate or focus light. The typeof application and spectral region usuallydictate the manufacturing methods, mater-ials and thin-film coatings used to producefinished optics.
There are numerous applications for mir-rors and thin-film coatings. One of the morecommon applications for mirrors is the con-trol of laser radiation. Other typical appli-cations include spectroscopy, imageprojection, military systems, telecommuni-cations, automotive and medical. Some appli-cations for mirrors are wavelength specific.For example, in the UV, typical applicationsinclude analytical chemistry, inductively cou-pled plasma spectroscopy, and excimer lasermicrolithography, micromachining andLASIK vision correction. Important recentadvancements of high laser damage thresh-old mirrors are making more demandingapplications feasible.
Typical VIS applications include projec-tion display optics, analytical instrumenta-tion, architectural lighting, militarysighting systems and automotive systems.In the IR spectral region, typical applicationsinclude Fourier transform infrared spec-troscopy as well as environmental monitor-ing, defence and aerospace applications.
Substrate materialsThere are few limitations on the optical mat-erials used for mirror substrates, which givethe designer great flexibility in terms of cost,strength, stiffness and aspect ratio. Materialsfor transmitting optics on the other handmust be carefully selected to ensure optimumlight transfer through a system.
Depending on the application, mirrors canbe produced from plastic, glass, metal orceramic substrates. Mirror substrates forlaser applications are normally manufac-tured using BK7, fused silica or CaF2. Sub-strate cost, surface figure, surface finish,thermal stability and structural integrity areall drivers for substrate choice.
Surface qualityAlong with selection of the proper sub-strate material, actual damage thresholdand long lifetime can greatly depend on thesurface preparation of the optics. Mostlaser optics are specified by surface figureand surface finish.
Surface figure is a measurement of thedeviation from an ideal surface, in terms ofpeak-to-valley waves. A typical specificationof 1/10-wave or better at 633 nm is com-mon for surfaces of excimer laser optics,although for some special applications, sur-face figure specifications can be in the rangeof 1/20 or better. Surface finish is defined asthe number of flaws in an optical surface interms of the scratches and digs, based ondocumented military specifications. Surfacefinish of an excimer mirror is typically spec-ified as 20–10 or better for optimum, low-scatter performance. In some criticalapplications, a surface finish of 10–5 or bet-ter is available. Precise fabrication tech-niques used to produce these types ofsurfaces, especially on crystalline materialssuch as MgF2 and CaF2, can contributegreatly to the overall optical performance ofthe excimer laser.
Types of mirrorTo meet the requirements of specific appli-cations, mirrors can be manufactured flat,spherical or aspherical. Each type of mirrorprovides unique optical properties for reflec-tion. A flat mirror will reflect light at thesame angle as the light that enters the mir-ror. A concave spherical mirror will focus orcollimate incoming light but may introducespherical aberrations. A parabola is oneexample of an aspheric mirror and thereforedoes not create spherical aberrations.Aspheric mirrors also include ellipsoids andtoroids, each with its own unique opticalproperties. Since aspheric mirrors are harderto manufacture, they are generally moreexpensive than spherical mirrors.
Thin-film coatingsThe majority of optical thin-film coatingsproduced today consist of alternating layersof high and low index dielectric materials, ora combination of dielectric and metallic lay-ers. Common dielectric materials include flu-orides such as MgF2, LaF3 and AlF3 andoxides such as SiO2, TiO2, Al2O3 and Ta2O5.Metals typically include aluminium for UVand VIS, silver for VIS and NIR and gold forNIR and IR wavelengths.
The arrangement of material layerswithin a coating “stack” allows productionof efficient antireflection (AR) coatings, neartotal reflectors, broadband mirrors, opticalfilters, beam-splitters and a host of otherlight control coatings. Careful selection ofcoating materials is an important step in themanufacturing process to yield high effi-ciency thin-film coatings. Choosing the bestcoating materials for a specific application isdictated by several factors, including thedesired optical properties, wavelength regionof interest, refractive index and absorption,inherent stress introduced by the materials,and environmental requirements for the fin-ished part. Candidate materials are routinelycharacterized by producing a test coating,which is measured to determine refractiveindex and absorption properties over thewavelength region of interest. Once the data
Critical components: mirrors precisely control lightin countless optical applications.
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is collected, it can be incorporated into a thin-film design programme for computer model-ling of coatings.
Thin-film modellingIt is possible to accurately model a wide varietyof thin-film coatings after you create a data-base of material properties (n and k) for avail-able coating processes. Commercial thin-filmdesign programmes enable the user to rapidlysimulate many different combinations ofmaterials and layers to achieve the desiredresults before operating the coating chamber.
Coating depositionThere are several physical vapour depositionprocesses capable of producing thin-filmcoatings, including electron beam (e-beam),ion-assisted-deposition (IAD) and resistiveheating. The e-beam process is popularbecause it enables deposition of dielectriccoating materials and can be used with IADfor the production of extremely durablecoatings. In addition, multi-pocket e-beamguns can hold several different materials,making it relatively easy to incorporatemore than two coating materials into adesign. Resistive heating is commonly usedfor metallic coatings and can also be used forcertain fluoride materials.
Optical monitoringTo facilitate production of more complexdesigns, a state-of-the-art optical monitoringsystem (OMS) has been developed, whichautomates the coating process and enables awide variety of standard and hybrid coatingsto be produced. The system works in con-junction with thin-film design programs to
enable a wide variety of coatings options.The OMS uses information from the thin-filmprogramme to calculate exact layer thick-ness and determines the “cut-point” for eachlayer. As layers are deposited, the OMS mon-itors and compares actual data to the com-puter model. It selects the appropriatecoating materials, deposits the layers andmakes adjustments as required to follow thecomputer model. For high-volume produc-tion, the automated OMS assures a highdegree of lot-to-lot consistency. In addition,any fraction or multiple of a quarter-wavelayer thickness can be deposited, creatingmany new and exciting possibilities for mir-ror coatings.
Anti-reflection coatingsThe purpose of an AR coating is to reduceunwanted reflections and to increase trans-mission within a desired wavelengthregion. AR coatings can range from a singlelayer MgF2 AR to traditional “V” coatings tomore complex broadband multi-layerdesigns (see diagram above). AR coatingsare routinely used on lenses, windows andback surfaces of beam-splitters to reduceunwanted reflections.
Broadband vs multi-layer dielectricsMirror coatings generally fall into two cate-gories which include broadband metallic orwavelength specific multi-layer-dielectric(MLD) designs. Common broadband metal-lic coatings include enhanced (or protected)aluminium, silver and gold. Overcoat layerscan include single dielectric layers such asMgF2 or SiO2, or MLD coatings to provideenhanced reflectivity and protection in
adverse environmental conditions. Wavelength-specific MLD mirrors, rou-
tinely used in high-energy laser applications,consist of alternating layers of high and lowindex materials to achieve near total reflect-ance at the design wavelength. Advantages ofMLD coatings are greater resistance to laserinduced damage, extremely low absorptionand near total reflectivity. It should be notedthat MLD coatings are relatively narrowreflectors compared to broadband metallicmirrors, with bandwidths ranging from5 to 20% of the design wavelength.
Advanced optics for high-powersemiconductor and medical lasersOver the past year there have been signifi-cant developments in damage resistant coat-ings for 193 nm medical and semiconductorlaser markets. Excimer lasers used in LASIKapplications typically operate at relativelyhigh fluence levels (~300 mJ/cm2) and mod-erate (200–400 Hz) repetition rates, subject-ing optical coatings to high average powerduring a typical vision-correction procedure.On the other hand, semiconductor lasersoperating at moderate fluence levels(~3–5 mJ/cm2) now achieve repetition ratesapproaching 3–4 kHz, continuously expos-ing mirrors to energetic UV radiation for bil-lions of laser pulses.
Taking advantage of the new OMS, hybrid193 nm mirrors were produced that satisfyboth medical and semiconductor require-ments. Coatings have been tested for morethan 2 million laser pulses at 300 mJ/cm2
(200 Hz) and greater than 8 billion laserpulses at 5 mJ/cm2 (4 kHz) without damage.In addition, the new hybrid coatings passMil-Spec adhesion, abrasion and humiditytesting, making them some of the mostrobust UV coatings available.
In summary, mirrors are critical compo-nents that precisely control light in countlessoptical applications. Selecting the right mir-ror for an application, however, is no trivialtask. The key to designing an effective andaffordable solution is to partner with a firmthat has expertise in your specific application.Several critical factors must be addressed toensure that the performance objectives willbe met and that the optic will survive theoperating conditions in your application.These factors include substrate material, sur-face figure, surface finish, mirror geometry,coating design and deposition method. Theoptimal solution is the result of a rigorous bal-ance of these important factors.
Michael Case is vice-president of research anddevelopment and Mark Dykstra is product managerof optics at PI/ACTON. For more information, seewww.piacton.com.
35OLE • May 2006 • optics.org/ole
wavelength in nanometers400
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uncoated fused silicasingle layer MgF2 AR“V” AR coatingbroadband multi-layer AR
Thin-film application: selection of AR coatings compared with an uncoated fused silica surface. ARcoatings are routinely produced for ultraviolet, visible or near infrared wavelengths.
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36 OLE • May 2006 • optics.org
Looking first at the show’s business pro-gramming, the event features a series ofmarket overview talks. “The sensor market isa pretty hot topic at the moment, particu-larly homeland security applications,”Colleen Morrison, the OSA’s director of pub-lic relations, told OLE. “We have talks provid-ing industry analysis, looking at the markettoday, where it is heading and how muchroom there is for growth.”
Other hot topics at the conference includeterahertz imaging, fibre lasers and high-power semiconductor lasers, with talks by bigplayers such as nLight, Alfalight and JDSU.“These are definitely some of the ‘hot-button’areas that we have seen,” said Morrison. “Forexample, the topic of fibre lasers has come uptime and time again in submitted papers,invited talks and even the plenary sessions.”
As part of the Photonics Applications, Sys-tems and Technologies (PhAST) event, dele-gates can register for a “Power Lunch” withindustry experts (to be held Monday 22 May,12.00 midday–1.00 p.m.). “It is designed tobe a one-on-one opportunity for attendees to
talk to some of the visionaries in the field,both on the research and the business sides ofthe industry,” explained Morrison. “The ses-sion has been a tremendous success in thepast and we have some fantastic namesinvolved this year.” Luncheon participantsinclude Randy Heyler, Newport’s director ofstrategic marketing, Philip Meredith, head ofJDSU’s laser products group, and KathleenPerkins, Breault Research Organization’schief executive officer.
The Power Lunch is followed by a free Busi-ness and Management Insights panel discus-sion, where delegates can expect to find outmore about business strategy, managementtechniques and start-up issues.
Turning to the busy technical pro-gramme, the Conference on Lasers and Elec-tro-Optics (CLEO) runs throughout the week.Its 15 packed sessions cover topics such asorganic LEDs, optical metrology, medical and
biological applications, ultra-fast optics andlaser processing to name just a few. If youthen add on the Quantum Electronics andLaser Science (QELS) event, it soon becomesclear that delegates can expect a busy fivedays at the Long Beach Convention Centre.In fact, according to the OSA, the 2006 con-ference packs in a total of nearly 1200 tech-nical sessions.
Highlights include DARPA’s deputy direc-tor, Robert Leheny, who will give a keynoteaddress on Defense Applications for Emerg-ing Opto-Electronic Technologies, detailingtrends and their future impact. Mario Panic-cia of Intel has been invited to discussprogress in silicon photonics as part of theCLEO programme and Stanford University’sJelena Vuckovic will speak about nanopho-tonic devices for quantum information pro-cessing. A full list of all the talks can be foundat the OSA’s website, www.osa.org.
CLEO/QEL S/PHASTHIGHLIGHTS 36 PRODUCTS 37
Great location: attendees can expect a warm reception at the Long Beach Convention Center.
CLEO/QELS takes place in LongBeach, California, US, on 21–26 May and is co-locatedonce again with the OSA’ssuccessful PhAST conference.OLE spoke with Colleen Morrisonto find out what delegates canlook forward to at the 2006conference and exhibition.
Sun 21 May Mon 22 May Tue 23 May Wed 24 May Thu 25 May Fri 26 MayRegistration ✓ ✓ ✓ ✓ ✓ ✓Short courses ✓ ✓ ✓Plenary sessions ✓ ✓CLEO/QELS technical sessions ✓ ✓ ✓ ✓ ✓Tutorials ✓ ✓ ✓ ✓ ✓Symposia ✓ ✓ ✓ ✓ ✓PhAST technical sessions ✓ ✓ ✓Exhibit ✓ ✓ ✓Innovation awards presentations ✓ ✓Business programming ✓ ✓ ✓Poster sessions ✓ ✓ ✓Career centre ✓ ✓ ✓Conference reception ✓Postdeadline paper session ✓*subject to change
Schedule at a glance*
OLEMayCLEO36 21/4/06 1.37 pm Page 36
Q-switchGooch & Housego
The VHE Q-switch fromGooch & Housego, UK,has been designed foruse in high-gain, high-power, linearlypolarized Nd:YAG andNd:YVO4 lasers.Supplied in an industry-standard package for
integration into existing cavities, the device issaid to provide better than 95% single-pass lossmodulation compared with around 85% fromconventional designs.
Traditionally, the only way to achieve the lossmodulation needed to Q-switch high-gainsystems was to fit two Q-switches in series toprovide sequential depletion of the zeroth orderbeam. Careful alignment of the acoustics withinGooch & Housego’s design means that, atcertain incidence angles, a laser will not bediffracted by an acoustic beam. These anglesare built into the VHE device to ensure that lightcannot be diffracted back into the zeroth order.www.goochandhousego.comBooth 1513A
Ultraviolet lasersTOPTICA Photonics
TOPTICA’s iPulse andiBeam diode lasersystems are nowavailable with outputpowers of up to 18 mW
at 375 nm, extending their appeal in biomedicalapplications such as fluorescence detection.Specifications also include a high-power stability(< 0.5%) and diffraction-limited beam quality.
Both the iPulse and iBeam can be equippedwith TOPTICA’s fibre-coupler FiberDock. At375 nm, the company says that the outputpower at the end of the fibre exceeds 11 mW,equating to an efficiency of > 65%. A thermo-stable design ensures that ambient temperaturedrifts no longer impact on the laser’s efficiency.www.toptica.comBooth 2012
Nd:YVO4 laserCoherent
The PRISMA 1064-32-Vfrom Coherent is adiode-pumped Nd:YVO4
laser that produces30 W at 1064 nm in a
TEM00 beam with pulse durations as short as18 ns and repetition rates from 20 to 100 kHz.Thanks to its high average power, the laser issaid to be ideal for micromachining smallfeatures at high-throughput rates.
Typical applications include solar cellprocessing, mould-form manufacturing, deepengraving and wafer scribing. The laser isavailable with accessory options such as abeam expander, visible aiming beam andmounting flange for scanner optics.www.coherent.comBooth 1331
PowermetersThorlabs
A family of opticalpowermeters forprecision optical powermeasurements, peakdetection and laser
adjustment is now available from Thorlabs.Offering easy handling alongside a favourableprice:performance ratio, Thorlabs can provideunits for optical powers in the range of5 nW–30 W and wavelengths between 250 nmand 10.6 µm.
The family comprises sets with standardsemiconductor and thermal sensors as well assets with thin profile sensors or integrating sphere
sensors. Products with a multifunctional digitalhand-held console or with a large, mirrored andeasy-to-read analogue display are available.www.thorlabs.comBooth 1402
ActuatorsPI
A line of high-performance actuatorsdubbed NEXLINE is nowavailable from PhysikInstrumente (PI). Theall-ceramic, high-
stiffness NEXLINE actuators providepushing/holding forces to 600 N, equivalent to130 lbs, and are quoted as having a resolutionof better than 0.1 nm. Standard actuators comewith a travel of 20 mm, but custom and OEMunits with much longer travel are feasible.
Due to zero-drift automatic locking when atrest, PI claims that the actuators can maintain aposition to nanometer-level precision for weeks,while dissipating no heat or consuming anyelectrical power. Due to the high stiffness, PIadds that they can be run in a special analoguemode for active vibration cancellation anddithering.www.pi.wsBooth 1524
SHOW PRODUCTS
37OLE • May 2006 • optics.org/ole
The CLEO exhibition returns to LongBeach, CA, US, on 23–25 May. The OLEteam brings you a preview of some of thenew products on show at the OSA event.
OLEMayCLEOPRODUCTS37-40 21/4/06 1.24 pm Page 37
M2 measurementPhoton Inc
Photon Inc of the UShas added an M2
Wizard option to itsNanoScan beam-profiling instrument.
The Wizard goes through a step-by-stepprocedure for manually measuring M2 using theNanoScan’s software. Based on the Rayleighmethod, the process involves making threebeam-size measurements.
For many low-to-moderate laser manufacturingapplications, a simple manual procedure tomeasure M2 is desirable. When full automation isrequired, Photon says that the NanoScan can beintegrated into its ModeScan fixture to create anautomated M2 measurement system. www.photon-inc.comBooth 1326
NIR spectrometerAvantes
Avantes has added theAvaSpec-NIR256 to itsrange of spectrometers.The new spectrometeris available with two
different InGaAs detector types: a non-cooledversion for applications of up to 1.7 µm and a
two-stage peltier-cooled extended detectorcovering a range of up to 2.2 µm.
A USB 2.0 interface is included in theAvaSpec-NIR256 to enable sampling of 940spectra per second with onboard averaging anddata transfer in only 1.56 ms. The spectrometeruses a 50 mm focal length optical bench with anf-number of 2 to maximize sensitivity. DifferentNIR-blazed grating are available to optimizeresolution and range.www.avantes.comBooth 1913
Shack–Hartmann sensorWavefront Sciences
Wavefront Sciences hasdeveloped aShack–Hartmannwavefront sensor forlong-range infrared
applications. The CLAS-LongIR-640 sensorfeatures a GaAs quantum well infraredphotodetector that operates from 8.0 to 9.3 µm.Its large diameter aperture allows users tomeasure beams that fit within an area of16×12.8 mm. However, larger diameter beamscan be accommodated by using beam-reducertelescopes designed to work with the sensor.Devices are commonly used to assess thewavefront quality of laser beams and light
sources. In addition, the CLAS-LongIR-640 canbe used to measure the transmitted aberrationsof Ge and ZnSe optical components.www.wavefrontsciences.comBooth 1638
Avalanche photodiodesLaser Components
Laser Components saysthat its siliconavalanche photodiodes(APDs) are a perfectmatch for its pulsedlaser diodes emitting at850 and 905 nm. Both
products are manufactured in-house. The APDsare being produced in volume and are availablefor CLEO 2006.
The company is also offering a low-cost, high-performance transmitter/receiver combinationwith the pulsed laser diodes and APDs.www.lasercomponents.co.ukBooth 1102
Fibre amplifierKEOPSYS
KEOPSYS, a provider ofhigh-power fibre lasersand amplifiers withlocations in France and
SHOW PRODUCTS
38 OLE • May 2006 • optics.org/ole
DiscoverNanophotonicsSpecial issue of Journal of Optics A: Pure and Applied Optics
The Fundamental Aspects of Nanophotonicsspecial issue explores the dimensions betweenthe objects the human eye can see through alens and those of the invisible elementarybuilding blocks of the material world.
It is essential reading for anyone involved innanophotonics research and for those workingon applications of this technology.
Readers of OLE can purchase their personalcopy for the special discounted price of£40/$68.
Visit www.iop.org/ej/jopa for full details.
OLEMayCLEOPRODUCTS37-40 24/4/06 10.57 am Page 38
the US, has released a 10 W continuous-wavepolarization-maintaining amplifier. Dubbed 10W-KPS-SLM-PM, the erbium-ytterbium fibre-basedunit has been engineered to amplify narrowlinewidth signals in the spectral range from 1530to 1565 nm. The standard 19 inch rack mountunit is said by the firm to include all controls,monitors, alarms and RS232 interfacesnecessary for system integration. Front paneltouch keys give the user access to the amplifier’sdifferent functions and parameters. Applicationslisted by the company include free-spacecommunications, frequency-doubling, coherentdetection and beam combining.www.keopsys.comBooth 1920
Modulated LEDsHORIBA Jobin Yvon
Intense light sources forfrequency-domainlifetime fluorescencespectroscopy are nowavailable from HORIBAJobin Yvon. Accordingto the company, the
modulated LEDs offer a depth of modulation farbeyond that of traditional Pockels cells.
The LEDs can be integrated into the FluoroLogTau-2 and Tau-3 systems. The company claimsthat the LEDs have an intensity of up to fivetimes the standard system using a xenon-arclamp plus a Pockels cell, with sine-wavemodulation frequency of 500 Hz–320 MHz.
Both collimated and focused beams areavailable in three wavelengths: 280, 295 and365 nm. More wavelengths will be released indue course.www.jobinyvon.co.ukBooth 1230
Ultraviolet DPSS lasersLaser-compact
Laser-compact ofRussia is offering arange of ultravioletDPSS lasers with outputof up to 40 µJ at351 nm, up to 20 µJ at
355 nm and up to 5 µJ at 266 nm. According tothe firm, the beam’s Gaussian profile allowsfocusing down to a spot size of around 1 µm.
Devices are available as complete lasersystems operating in pulsed mode with pulsedurations of less than 10 ns and a choice ofinternal or external triggering. OEM versions canalso be supplied by the company along with anindustrial model dubbed GARNET. Applicationsinclude mass spectrometry, lasermicrodissection, biotechnology and variousresearch and development uses.www.laser-compact.ruBooth 1849
Vibration isolation platformMinus K
Minus K Technology hasexpanded its range oflow-profile, compact,vibration isolation
platforms. Measuring 12×12×4.7 inches, theBM-10 isolator is said to be ideal for thecombination of small instrumentation andlimited bench space. The platform offers 0.5 Hzvertical natural frequency and 1.5 Hz horizontalnatural frequency and is available in a range ofmodels to support payloads from a few gramsup to 25 kg.
Thanks to its patented “negative stiffness”technology, the US firm claims that the isolationplatform outperforms active and air-basedsolutions. Easy to transport from lab to lab, theisolator is quick to set up and operate. Pricingstarts at $2300 (71890).www.minusk.comBooth 1848
Fibre-optic couplerBristol Instruments
Bristol Instruments, acompany founded byformer employees ofBurleigh Instruments,has introduced the LCseries of fibre-optic
laser couplers. Consisting of a 1 inch mountingdisc attached to 3 m of 9 µm core-diameterfibre, the LC couplers can be used to launch afree-space laser beam into a fibre or return thelaser to a collimated free-space beam. The LC-1includes built-in alignment optics that providetwo slightly off-axis back reflections to facilitatealignment. The LC-2 is identical to the LC-1, butwithout the alignment optics.www.bristol-inst.comBooth 1226
Optical accessoriesMelles Griot
Melles Griot has addedoptomechanicalhardware andpositioners to its onlinecatalogue andexpanded the available
range of optics to include lead-free achromats,variable-density filters, long-pass and notchfilters, and laser-line beamsplitters.
Other updated items include high-power andhigh-contrast polarizers, together withfluorescence-microscopy filters and achromaticretardation plates. According to the firm, mosthardware components are in-stock items andare available for immediate delivery at attractiveonline prices.www.mellesgriot.comBooth 1425
SHOW PRODUCTS
39OLE • May 2006 • optics.org/ole
OLEMayCLEOPRODUCTS37-40 21/4/06 1.22 pm Page 39
Laser galvanometer headAerotech
Aerotech’s A3200motion and machinecontrol platform nowfeatures an integratedgalvanometer head toenable laser marking.The unit combines
1–32 axes of FireWire distributed motion controlwith HMI, PLC and vision control modules. Twoversions are available – the Nmark VCT, whichsuits vector laser marking of lines, arcs andcircles, and the Nmark GRC, which supportsraster-scan marking. Both set-ups are software-integrated to allow multi-axis machining,including marking on-the-fly and z-focus heightcontrol for 3D processing. Applications includemicrohole drilling on a range of thin metal andnon-metallic substrates, along with barcodingand character scribing.www.aerotech.comBooth 1525
Diode laserOndax
Ondax of California, US,has introduced awavelength stabilizeddiode laser emitting at658 nm. Stabilization isachieved using a
volume holographic grating dubbed thePowerLocker. According to the firm, thePowerLocker is ideal for increasing the spectralbrightness of laser diodes, locking theirwavelength and improving temperature stabilityand yield. Ondax’s laser diode has a single-mode, narrow linewidth of <100 MHz and a verylow temperature dependence of 0.01 nm/°C. Itis housed in a standard 5.6 mm TO package.Applications listed by the company includemetrology, sensing and Raman spectroscopy. www.ondax.comBooth 2027
Digital imagingAndor
Andor Technology, aprovider of digitalcameras for scientificapplications, hasreleased a newcatalogue and updatedits website. Both thecatalogue and websiteoffer an overview of
digital camera technology and feature anapplications section showing where the variousproducts and accessories are being used.According to the firm, its range of CCD, EMCCDand intensified CCD camera systems suitacademic, industrial and government research
across a broad range of fields, such asbiotechnology, physics and chemistry.www.andor.comBooth 1924
Optical gas sensorCascade
Cascade Technologieshas demonstrated traceexplosive fingerprintingand detection using itsquantum cascadelasers (QCLs). What’smore, the UK-basedfirm believes that thiscapability can betransferred into acommercial fieldinstrument that will becompact, robust andcost-competitive.
The company saysthat QCL detection isover 1000 times moresensitive than FTIRmeasurements andallows fingerprints to be
recorded in real-time with a resolution of< 0.005 cm–1.
Thanks to its large spectral window, theapparatus allows simultaneous detection ofmultiple species and the identification ofcomplex molecules such as those found in drugsand explosives. Other applications for the firm’sQCL devices include LIDAR, range-finding andproduct characterization.www.cascade-technologies.comBooth 1225-C
Tunable UV laserEKSPLA
The NT340/UVE seriesof tunable Q-switchedlaser systems fromEKSPLA offer hands-free, continuous tuningbetween 210 and420 nm and the ability
to tune up to 2300 nm. Emitting up to 5 mJpulses in the ultraviolet, the range is said by thecompany to have a wide range of targetapplications including photobiology, remotesensing, photolysis and LIDAR.
The system comprises a nanosecond, Q-switched Nd:YAG pump laser and an opticalparametric oscillator (OPO) in a single compacthousing. According to EKSPLA, the systemrequires only a few seconds to warm up and canbe controlled using supplied LabView drivers ora user-friendly remote control pad. The standardsystem also has a separate output at 355 nm.www.ekspla.comBooth 1840
SHOW PRODUCTS
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40 OLE • May 2006 • optics.org/ole
OLEMayCLEOPRODUCTS37-40 21/4/06 1.22 pm Page 40
Laser powermeterScientech
Scientech of Colorado,US, is introducing acompact, portablepowermeter that it saysis ideal for analysinghigh-power YAG and
CO2 lasers. The firm’s RAD system comprises ahand-held indicator unit housed in a ruggedmetal case and a 60 mm aperture water-cooleddetector. The detector contains a high damagethreshold, broadband absorber that has a rangeof 5–1000 W.
Features include a four-digit LCD display,wavelength compensation, beam alignment andLED sensor overload warning. Options such as arechargeable lithium-poly battery, USB datainterface and convenient mounting system arealso available.www.scientech-inc.com
Off-axis parabolic mirrorsSpectrum Scientific
Spectrum Scientific isoffering low-cost,custom off-axisparabolic mirrors withsurface qualities of up
to λ/10 or better and 60:40 scratch dig. The USfirm manufactures its optics by firstly producinga master and then transferring the opticalquality of the master to a substrate through areplication process rather than conventionalpolishing. Often, an existing mirror can be usedas a master, leading to further cost-savings.
Replicated mirrors can be produced onsubstrates such as glass (typically crown, fusedsilica or Pyrex) or metal (typically aluminium,stainless steel or beryllium). The company addsthat metallic substrates can incorporate tabs,mounting holes or brackets to produce anintegrated mounted optic. The replicationprocess can also be used to manufactureparabolic mirrors, elliptical mirrors and cube-corner retroreflectors.www.ssioptics.com
Digital pyrodetectorPerkinElmer Optoelectronics
PerkinElmerOptoelectronics, US,has introduced theDigiPyro PYD 1998,which it says is the firstdigital pyroelectricinfrared sensor for
industrial motion detection applications. Thedevice is the first in a new series of digitalpyrodetectors from PerkinElmer.
The dual-element pyrodetector is said toprovide OEMs with performance advantagesover traditional analogue pyrodetectors andreduces the cost and space requirementsassociated with analogue circuitry. It also boastssignificantly improved EMI immunity.
PerkinElmer says that the power supplyrejection ratio is improved by 30 dB, a 32-foldimprovement over traditional analoguepyrodetector technology.www.optoelectronics.perkinelmer.com
Dichroic filtersUnaxis Optics
The LED ColorDichroicfilters and mirrors, nowavailable from UnaxisOptics, efficiently reflectand transmit random
polarized light from multiple LEDs of differentwavelengths into one single beam. Typicalapplications for these components includeprojection display illumination optics and solid-state lighting.
LED ColorDichroics are usually arranged at45° relative to the orientation of the differentLEDs. Manufactured using Unaxis’ optical sputter
coating technology, the products are coated onflat borosilicate substrates with a standardthickness of 0.7and 1.1 mm. Other glass typesand thicknesses are available on request.www.optics.unaxis.com
3D scan systemSCANLAB
The intelliWELD 30 FC,a smart and compact3D scan system forhigh-power disc or fibrelasers, is now available
from SCANLAB. Designed for robot-assistedwelding applications, the system is said to becapable of swiftly positioning a laser beamalong 3D contours.
Despite its 30 mm aperture, the systemoccupies a small volume and the company saysthat it is easy to mount on welding robots, evenin space-sensitive locations. Optics in the 30 FCproduct are optimized for fibre-coupled laserswith powers of up to 5 kW. SCANLAB adds that adual-pane protective window and the long 0.5 mworking distance both help to protect the scanobjective from welding splatter.www.scanlab.de
PRODUCTSIf you would like your company’s products to be featured in this section,
please send press releases and images to James Tyrrell ([email protected]).
41OLE • May 2006 • optics.org/ole
YG980so Stable, so Reliable,
so Efficient
[email protected] - +33 1 69 29 17 00 / [email protected](406) 586 0131
Quantel & Big Sky Laser
YG980 Series: the solution for all your high beam quality nanosecond Nd:YAG laser needs. • From 0.4 to 2.4J per pulse @ 1064nm in ~10ns• Motorized harmonic generation and separation• Divergence <0.5mrad• Repetition rates up to 50Hz • Single longitudinal mode option for narrow linewidth applications(with injection seeder)• Remote box or external software controlQuality and innovation guided Quantel in the development of theYG980 Series.
OLEMayPRODUCTS41-45 21/4/06 1.25 pm Page 41
Integrating sphereAnalytical Spectral Devices
Analytical SpectralDevices (ASD) hasreleased the RTS-3ZC, aspecially designedintegrating sphere foruse with its FieldSpecspectroradiometers.
The company says that the accessory allowsusers to make accurate reflectance ortransmittance measurements of diffuse orscattering materials such as those found inmany optical remote-sensing applications.
For example, radiation balance and plantcanopy modelling studies often requiremeasurement of hemispherical reflectance andtransmittance of real-world samples. According toASD, the integrating sphere is ideal for thesemeasurements because it collects all the radiationreflected from, or transmitted through, a sample.www.asdi.com
Ammonia monitorPicarroThe ESP-1000 from US firm Picarro uses cavityring-down spectroscopy (CRDS) to detectammonia to below one part-per-billion inambient air. Targeted to meet the needs of thesemiconductor industry, the ESP-1000 enablesreal time monitoring of airborne ammonia inapplications such as lithography.
According to Picarro, ammonia exposure is awell-documented issue for advanced lithographywhere even part-per-billion levels can lead towafer loss and unscheduled downtime of criticallithography equipment. The firm has alsoapplied its CRDS technology to make ultra-sensitive measurements of a variety of othergases including CO2 and isotropic CO2, H2O andisotropic H2O and H2S.www.picarro.com
MonochromatorMcPherson
Multiple-pass, double-dispersion accessoryoptics are nowavailable for 0.67–2 mfocal lengthmonochromators fromMcPherson. According
to the firm, multiple-pass monochromators allowusers to work with low f/number, twice theresolution and excellent throughput.
The unique doubling of resolution anddispersion is achieved by plane-folding mirrorsthat multiply the monochromator focal length.The instrument is said to be ideal forexperiments where more spectral resolution isrequired and lab space or budget cannotaccommodate a physically larger instrument.www.mcphersoninc.com
PRODUCTS
MAKE LIGHT | MANAGE LIGHT | MEASURE LIGHT
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Oriel MATRIX Spectrometer
The first UV-VIS dispersiveinstrument with MMS inside
Finally, a spectrometer that doesn’t require acompromise between throughput andresolution. Newport's new Oriel MATRIXspectrometer is a truly revolutionaryinstrument; its unrivalled throughput andSNR let you measure very weak signals in the190 to 500 nm spectral range, with aresolution of 0.6 nm.
It’s the first UV-VIS dispersive instrument toincorporate new patented MMS (MultimodalMultiplex Spectroscopy™) optical sensingtechnology, offering key advantages overtraditional spectrometers, including:
• 12X more throughput withoutcompromise in resolution
• 12X more signal to noise ratio, formeasurement of very weak, scatteringor diffuse sources
• Free space, for greatest inputflexibility
This completely integrated system is ideallysuited to applications such as fluorescence,thin film reflectance, and atomic emission.
To learn more about Newport’s new OrielMatrix Spectrometer, give us a call ordownload a datasheet at:
www.newport.com/mms.
PicosecondPicosecond
Diode LasersDiode Lasers
EPL 375
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*Typical value may vary with model.
OLE • May 2006 • optics.org/ole
OLEMayPRODUCTS41-45 21/4/06 1.25 pm Page 42
LEDsOsram
Osram’s PowerTopLEDswith 30 and 60° beamangles are nowavailable with newlevels of brightness. Thecompany quotes6300 mcd in super-red,
12000 mcd in amber and 650 mcd in yellow fora typical forward voltage of 3.4 V.
According to Osram, another advantage of the30 and 60° PowerTopLEDs is their SMTpackage. This enables the devices to beprocessed using standard solder techniques,which in turn reduces placement costs. Heat canalso be effectively dissipated via the LED’s four“legs”. Osram is targeting these new LEDs atsignage applications.www.osram-os.com
MicroscopesWITec
WITec of Germany hasreleased the alpha300series of modularmicroscopes, whichallows the combinationof different microscopytechniques in oneinstrument. The series
includes the confocal Raman alpha300Rmicroscope, the scanning near-field alpha300Soptical microscope and an atomic forcemicroscope branded the alpha300A.
All of the above are driven by a digital controlunit called the alphaControl. This unit is said toenhance speed, flexibility, accuracy and timingprecision. According to WITec, the microscopesare ideal for any applications where acomprehensive understanding of the samplestructure and composition is necessary.www.witec.de
Wafer-dicing systemJPSA
The IX-300 ChromaDicesolid-state UV laserwafer-dicing system isnow available fromJPSA of the US.According to the firm,the product operates at
cut rates of up to 150 mm/s on GaAs with kerfwidths typically down to 2.5 µm.
JPSA’s IX-300 ChromaDice system canprocess wafers up to 6 inches in diameter anduses efficient UV-DPSS laser technology ateither 355 or 266 nm. The technology is nowavailable in the high-volume, high-duty cycle IX-300 format or the smaller-footprint, lower-dutycycle and lower-cost IX-200 package.www.jpsalaser.com
PRODUCTS
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OLEMayPRODUCTS41-45 21/4/06 1.59 pm Page 43
Harsh environment housingFirstsight Vision
IDS’s range of USB 2.0uEye cameras formedical and industrialapplications now comeswith an IP67-compliant
housing for use in harsh environments. Availablethrough Firstsight Vision of the UK, the roughenvironment (RE) housing has been developedfor industrial environments where water, dust orother particulates are a problem.
The uEye RE series features models withmonochrome or colour CMOS or CCD sensors.The cameras are available with or withoutonboard memory and with resolutions rangingfrom 640×480 up to 2048×1536 pixels. Allmodels are fitted with a universal opto-decoupled trigger input as well as an opto-decoupled output for operating a flash.www.firstsightvision.com
Intensity measurementsRadiant Imaging
Radiant Imaging’s PM-GONI enables high-resolution, far-fieldluminous intensitydistribution and colourmeasurements of awide range of
illumination products. These include wide beamangle sources such as automotive headlampsand tail-lights, architectural lighting, trafficsignals and aircraft lighting.
According to Radiant, the PM-GONI is aturnkey system that mates a CCD-basedphotometer or colourimeter and a two-axisgoniometer together with system control, dataacquisition and image processing software. ThePM-GONI is compatible with all of Radiant’s PM-series of imaging photometers andcolourimeters.www.radiantimaging.com
Lens surfacing systemSatisloh
The All-Format Line fromSatisloh of Germany isa fully integratedflexible lens surfacingsystem that fullyautomates both
generating and polishing processes. Combininghigh-speed toric processing with free-formcapability to produce any complex surface, thetool eliminates hard lap tools, reduces labourand improves lens quality due to reduced formerrors. An open platform lab managementsoftware package is also available that allowsusers to attach multiple free-form lens designprogrammes to the All-Format Line.www.satisloh.com
PRODUCTS ModeScanM2 Measurements
...Automatically...Accurately
...Quickly
www.photon-inc.com
ModeScan:♦♦ Fully automated M2
measurements♦♦ CW or pulsed beams♦♦ Available for wavelengths
from 190nm to >20µm♦♦ Real-time divergence
measurement♦♦ Parameters measured♦♦ Times diffraction limit: M2
♦♦ Beam waist size: d0♦♦ Beam waist location: Z0♦♦ Divergence: θ♦♦ Rayleigh range: Zr
OLEMayPRODUCTS41-45 21/4/06 1.27 pm Page 44
Laser markingPTG
Florida-based PTGIndustries, US, hasreleased the FiberTowerDesktop, the latestproduct in its fibre-laser
suite. The firm says that the Desktop is the firstlaser of its kind to have an integrated controllerfor the laser, Z-axis, and scan-head. Thecompact system has plug-and-play capabilityand draws power from a 100 V AC outlet. Thecompany claims that the unit offers greateraccuracy with a 90% smaller spot size than CO2
versions, has a minimum of 50 000 hmaintenance-free operation and an excellentbeam quality (M2 < 1.05). These features, saysPTG, provide convenience for users in areassuch as precision marking of production parts.www.ptgindustries.com
LED backlightsGlobal Lighting Technologies
Global LightingTechnologies (GLT) ofthe US continues toexpand its range ofsingle-LED light guides,
which feature the firm’s patented Microlenstechnology. Today, GLT offers backlights in sizesfrom 6.5 mm to just under 400 mm diagonal.Available as single LED monochrome, bi-colour
or tri-colour options, GLT says that the pixel-based light extraction technology providesbacklighting with higher brightness, crisp colourand approximately 80–85% uniformity. Theextremely thin (< 0.6 mm) light guides offer alow power consumption of 1–20 mA at 3.5 Vand the cost advantages of a small-form, few-component design. According to the company,applications include 3G mobile phone displaysand microdisplays in digital and still cameras.www.glthome.com
Digital colour sensorsAvago
Avago has introducedwhat it says is anindustry-first in CMOSdigital colour sensors.According to the firm,
the ADJD-S313-QR999 can be directly interfacedto the system microcontroller without the need foradditional components. The RGB sensor issupplied in a lead-free package and, measuringjust 5×5×0.75 mm, is said to be 50% thinnerthan its closest competitor. The device operatesfrom a 2.6 V supply voltage and is said to offerlow power consumption. According to its makers,the sensor suits applications such as mobilephones, MP3 players and PDAs. Other usesinclude colour measurement in portable medicalinstruments and colour detectors.www.avagotech.com
PRODUCTS
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OLE • May 2006 • optics.org/ole
AP Technologies www.aptechnologies.co.uk 32
B&W Tek www.bwtek.com 30Berliner Glas www.berlinerglas.com 43BFI Optilas International www.bfioptilas.com 19
Breault Research Organizationwww.breault.com IFC
Cambridge Technologywww.cambridgetechnology.com 29
CVI Technical Optics www.cvilaser.com OBCEdinburgh Instruments www.edinist.com 42Edmund Optics www.edmundoptics.co.uk 30EKSPLA www.ekspla.com 40ELCAN Optical Technologieswww.ELCAN.com/create 18
Esco Products www.escoproducts.com 32Fujian Castech Crystals www.castech.com 37Fundamental Aspects of Nanophotonicswww.iop.org/ej/jopa 38
Global Laser Technology Solutionswww.globallasertech.com 14
High Q Laser Production www.highQlaser.at 44
i-Chips www.i-chipstech.com 33Imagine Optic www.imagine-optic.com 28Kentek Corp www.kentek.com 9
Laser Components (UK) Ltdwww.lasercomponents.co.uk 12, 13
Lasermet www.lasermet.com 20LIMO Laser Systems www.limo.de 20Melles Griot www.mellesgriot.com 15, 46Newport Spectra-Physicswww.newport.com 42
Ocean Optics www.oceanoptics.com 23Ophir Optronics www.ophiropt.com 6, 7, IBCoptics.org www.optics.org 43Optikos www.optikos.com 30PCO AG www.pco.de 39Photonic Solutions www.psplc.com 22Photonics West 2007www.spie.org/events/pw 26
Photon Inc www.photon-inc.com 44Quantel www.quantel.fr 41Quintessence Photonicswww.QPClasers.com 10
Scitec Instruments www.scitec.uk.com 20Spectrogon www.spectrogon.com 38Stanford Research Systemswww.thinkSRS.com 4
StockerYale Canada www.stockeryale.com 30
Toptica www.toptica.com 45Wahl Optoparts www.wahl-optoparts.com 30
ADVERTISERS’ INDEX
The index is provided as a service and, while every effort is made to ensure its accuracy, Optics&LaserEurope accepts no liability for error.
OLEMayPRODUCTS41-45 25/4/06 3.21 pm Page 45
PEOPLETo advertise your job vacancies, contact Cadi Jones (tel: +44 (0)117 930 1090; e-mail: [email protected]).
46 OLE • May 2006 • optics.org/ole
SUDOKU PUZZLE
We hope you enjoyed April’s Sudoku puzzle. Youcan check your answers against last month’ssolution on the left.
If you are new to Sudoku, this is how it works:each puzzle consists of a 9×9 grid that issubdivided into 9 smaller grids of 3×3 squares.To complete the puzzle, you must ensure thateach row, column and 3×3 square contains thenumbers 1–9. All it takes is logic so try not toguess at the numbers.
US
Jim Phelps becomes vice-president of quality at CVI
Optical componentsfirm CVI Laser haspromoted Jim Phelpsfrom the position ofquality director tovice-president ofquality. In this newrole he will co-
ordinate CVI’s quality initiatives on aworldwide basis. Prior to joining CVI, Phelpsspent 18 years at Coherent and has alsoworked as optical systems production engineerat Lawrence Livermore National Laboratory’sNIF facility in the US.
US
IRIDEX hires productinnovation specialistIRIDEX, a provider of medical lasers for eyetreatment and cosmetic surgery, hasappointed Deborah Tomasco as its new vice-president of product innovation. Tomascohas more than 20 years’ experience in rapidproduct development and has spent the pastseven years as a consultant. Previously, sheworked at Lifescan, a developer of bloodglucose monitoring systems, as programmedirector of operations.
US
Lucent makes Hitchcockits corporate controller
Lucent Technologieshas moved DavidHitchcock from therole of businessoperations andfinance vice-president to theposition of corporate
controller. He succeeds John Kritzmacherwho was appointed as chief financial officerearlier this year. Hitchcock joined Lucent’spredecessor, AT&T, in 1983 and has held awide range of financial roles.
GERMANY
Stephan Geiger moves toROFIN/ Baasel Lasertech
Stephan Geiger willjoin ROFIN/BaaselLasertech in May tomanage the firm’srecently formed“New Technologies”business unit, andwill oversee the
development of new laser sources andsystems. Recently, Geiger was responsible forsolid-state laser technology at Bavarian
Photonics, a firm that he co-founded in2002. Previously, he was vice-president ofresearch and development at TuiLaser, theparent company of Bavarian Photonics.
Geiger began his career back in 1985 atROFIN’s marking division. He holds a diplomain physical engineering from the University ofApplied Sciences in Munich, Germany.
BELGIUM
Umicore attracts new CFOto complete reshuffle
Umicore, theBelgium-basedmaterials specialist,has appointedMartine Verluyten aschief financial officer(CFO) commencingon 1 June. She iscurrently CFO of
Mobistar, a mobile phone operator and oneof Belgium’s most successful publicly listedcompanies in recent years.
At Umicore, Verluyten will take over theCFO role from Marc Grynberg who succeedsMartin Hess as executive vice-president ofthe company’s automotive catalyst division.Hess will move across to Umicore’s zincspecialities business as executive vice-president, while also overseeing the firm’scorporate development effort.
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OLEMayPEOPLE46 24/4/06 10.36 am Page 46
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We don’t make LasersBut we sure know how to
Measure them
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