BOOK OF ABSTRACTS - Wojskowa Akademia Techniczna...Polarization resolved laser produced aluminium plasma emission 12.45-13.00 A. Comisso Characterization of TiO 2 thin films and novel

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BOOK OF ABSTRACTS

Institute of Optoelectronics Military University of Technology

Warsaw, Poland

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The EXTATIC Welcome Week Workshop 2014 takes place in Warsaw (Poland) from

October 20th

to 24th

, 2014. The Workshop is organized under the Erasmus Mundus Joint

Doctoracte programme of the European Union on Extreme-ultraviolet and X-ray Technology

and Training for Interdisciplinary Coorporation (EXTATIC).

The aim of the EXTATIC Workshop 2014 is to provide an international forum for the

EXTATIC doctoral candidates to present and discuss their scientific achievements as well as

introduce new candidates starting the Programme this year.

Scope of the Workshop

The scope of the EXTATIC Welcome Week Workshop 2014 covers all aspects of EUV and

X-ray science and technology that exist in the EXTATIC Programme:

Laser and electrical discharge based light sources

Radiobiology

Optical systems

EUV and X-ray metrology

EUV nano-structuring and ablation of materials

Photoionization studies

Workshop webpage: http://www.ztl.wat.edu.pl/zoplzm/extatic/

http://erasmusmundus.org.pl/

3

Committees

Scientific Committee

Inam Ul Ahad (Military University of Technology, Poland)

John Costello (Dublin City University, Ireland)

Henryk Fiedorowicz (Military University of Technology, Poland)

Przemysław Wachulak (Military University of Technology, Poland)

Organizing Committee

Inam Ul Ahad (Military University of Technology, Poland)

Daniel Adjei (Military University of Technology, Poland)

Mesfin Getachew Ayele (Military University of Technology, Poland)

Alfio Torrisi (Military University of Technology, Poland)

Andrzej Bartnik (Military University of Technology, Poland)

Henryk Fiedorowicz (Military University of Technology, Poland)

Karolina Płatek (Military University of Technology, Poland)

Przemysław Wachulak (Military University of Technology, Poland)

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Invited Speakers

Invited Lectures

1. Maciej Kozak – Synchrotron radiation and application in biology

2. Ryszard Sobierajski – X-ray free electron lasers and applications

3. Janusz Lekki – Radiobiology research using microfocus X-ray tube

4. Przemysław Wachulak – Nanoimaging using soft X-ray and EUV sources

Introductory Lectures

1. Eckhardt Foerster – X-ray optics and spectroscopy

2. Libor Juha – Interaction of EUV and X-ray pulses with matter

EXTATIC Partners Presentations

1. John Costello (DCU) – Research facilities and programmes at DCU and

internationally

2. Serhyi Danylyuk (RWTH) – EUV applications at RWTH Aachen

3. Jiri Limpouch (CTU) – Research of plasmas produced by intense laser pulses

and by capillary discharges at FNSPE CTU in Prague

4. Piergiorgio Nicolosi (UP) – EUV optics research at Padova

5. Tom McCormac (UCD) – Atomic, molecular and plasma physics at UCD

6. Henryk Fiedorowicz (MUT) – Laser plasma sources of soft X-rays and

extreme ultraviolet (EUV)`for application in science and technology

Associated Partners Presentations

1. Michael Meyer (European XFEL) - Investigations of atomic and molecular

photoionization dynamics at short-wavelength Free-Electron Lasers

2. Leszek Dobrzanski (ITME) - Photodetectors and diffractive optics at ITME

3. Martin Regehly (greateye) - Low readout-noise CCD-cameras for UV, VUV,

EUV and X-ray imaging and spectroscopy

4. Ladislav Pina (RIGAKU) -

ERS Invited Presentations

1. Bartłomiej Jankiewicz - Plasmonic nanostructures for applications in surface

enhanced spectroscopies, photocatalysis and photovoltaics

2. Przemysław Zagrajek - Detectors of THz radiation based on FETs

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Programme Monday, October 20

th, 2014

15.00-15.15 Opening

15.15-16.00 M. Kozak (invited)

Synchrotron radiation - selected application in biology

16.00-16.30 I.U. Ahad

Extreme ultraviolet surface modification of polymers for biomedical

engineering applications Extreme ultraviolet surface modification of polymers

for biomedical engineering applications

16.30-17.00 Coffee break

17.00-17.30 D. Adjei

Development and application of a compact laser plasma soft X-ray source for

radiobiology experiments

17.30-18.00 H. Kim

EUV interference lithography with fractional Talbot effect

Tuesday, October 21st, 2014

09.00-09.45 R. Sobierajski (invited)

X-ray free electron lasers and applications

09.45-10.15 G. Bayene

Sn based laser assisted vacuum arc EUV source

10.15-10.45 F. Nawaz

Capillary discharge based XUV sources and applications in imaging


11.15-12.00 J. Lekki (invited)

Radiobiology research using a microfocus X-ray tube

12.00-12.15 M. Ayele

Compact laser plasma soft X-ray source for contact microscopy experiments

12.15-12.30 M. Tryus

Development of near-edge multi-angle spectroscopic EUV reflectometry

12.30-12.45 G. Wubetu

Polarization resolved laser produced aluminium plasma emission

12.45-13.00 A. Comisso

Characterization of TiO2 thin films and novel TiO2/Sc multilayers in the EUV

and soft X-ray region

13.00-15.00 Lunch break

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15.00-15.45 P. Wachulak (invited)

Nanoimaging using soft X-ray and EUV sources

15.45-16.00 Hu Lu

Photoabsorption in ultrashort duration UV and VUV laser fields

16.00-16.15 M. Odstracil

Coherent diffraction imaging using laboratory light sources

16.15-16.30 R. Loksani

Laser-produced plasmas of Mo, Ru, Rh and Pd in the 2 to 13nm spectral

region


17.00-17.15 M. Miszczak

Optics for short pulse X-ray sources

17.15-17.30 S.J. Davitt

The slit-less spectrometr: a compact Fourier transform spectrometer with no

moving parts

17.30-17.45 W. Hanks

Numerical modelling of laser-plasma interaction

Wednesday, October 22nd

, 2014

09.30-10.15 E. Foerster (invited)

X-ray optics and spectroscopy

10.15-11.00 L. Juha (invited)

Interaction of EUV and X-ray pulses with matter


11.30-12.00 J. Costello (DCU presentation)

Research facilities and programmes at DCU and internationally

12.00-12.30 S. Danylyuk (RWTH presentation)

EUV applications at RWTH Aachen

12.30-13.00 J. Limpouch (CTU presentation)

Research of plasmas produced by intense laser pulses and by capillary

discharges at FNSPE CTU in Prague


15.00-15.30 M. Meyer (DESSY invited presentation)

Investigations of atomic and molecular photoionization dynamics

at short-wavelength Free-Electron Lasers

15.30-16.00 L. Dobrzański (ITME invited presentation)

Photodetectors and diffractive optics at ITME

16.00-16.30 M. Regehly (greatye invited presentation)

Low readout-noise CCD-cameras for UV, VUV, EUV and X-ray imaging and

spectroscopy


17.00-17.30 L. Pina (RIGAKU invited presentation)

18.00-20.00 Dinner

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Thursday, October 23rd

, 2014

09.00-09.30 P. Nicolosi (UP presentation)

EUV optics research at Padova

09-30-10.00 Tom McCormack (UCD presentation) Atomic, Molecular and plasma physics at UCD

10.00-10.30 H. Fiedorowicz (MUT presentation)

Laser plasma sources of soft X-rays and extreme ultraviolet (EUV)

`for application in science and technology

10.30-11.00 Doctoral Panel meeting


11.30-13.00 Doctoral Panel meeting


15.00-17.00 Laboratory tour/Executive Management Committee Meeting

Friday, October 24th

, 2014

09.00-11.00 EXTATIC project presentations DC 2014

A. Torrisi

Nanoscale imaging using compact laser plasma SXR sources based on a

double stream gas-puff target and Fresnel optics

E.F. Barte

Using microstructures for laser-induced X-ray source enhancement from

plasma produced by femtosecond and nanosecond lasers

J. Bussmann

Coherent diffractive imaging employing a compact discharge plasma EUV

light source

D. Kos

A.E.H. Gaballah


11.30-12.00 B. Jankiewicz (ESR invited presentation)

Plasmonic nanostructures for applications in surface enhanced spectroscopies,

photocatalysis and photovoltaics

12.00-12.30 P. Zagrajek (ESR invited presentation)

Detectors of THz radiation based on FETs

12.30-13.00 Summary & Closing

13.00-15.00 Lunch

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2014 EXTATIC Welcome Week Workshop October 20-24, 2014, Warsaw, Poland

Time Schedule

Time Monday Time Tuesday Time Wednesday Time Thursday Time Friday

Arrival 09.00-09.45

Invited presentation

IP -2

R.Sobierajski

09.00-09.30

Registration &

Opening

09.00-09.30

EXTATIC Partner

Presentation P.Nicolosi

09.00-11.00

EXTATIC projects

presentations (DC 2014

+ supervisors)

A. Torrisi

E.F. Barte

J. Bussmann

D. Kos

A. Gaballah

09.30-10.15

Introductory lecture 1

E. Foerster

09.30-10.00

EXTATIC Partner

Presentation T.McCormack 09.45-

10.15 DC 2012-4

G. Beyene

10.00-10.30

EXTATIC Partner

Presentation H.Fiedorowicz

10.15-10.45

DC 2012-5

M. Nawaz

10.15-11.00

Introductory lecture 2

L. Juha

10.30-11.00

Doctoral Panel meeting

10.45-11.15

Coffee Break

11.00-11.30

Coffee Break

11.00-11.30

Coffee Break

11.00-11.30

Coffee Break

11.15-12.00


IP -3

J. Lekki

11.30-12.00

EXTATIC Partner

Presentation J. Costello

11.30-12.00

Doctoral Panel meeting: ;

finalise doctoral agreement,

discuss modules

specific to institution

11.30-12.00

ESR Presentation

B.Jankiewicz

12.00-12.15

DC 2013-1 M. Ayele

12.00-12.30

EXTATIC Partner

Presentation S. Danylyuk

12.00-12.30

12.00-12.30

ESR Presentation P.Zagrajek

12.15-12.30

DC 2013-2 M. Tryus

12.30-12.45

DC 2013-3 G. Wubetu

12.30-13.00

EXTATIC Partner

Presentation J. Limpouch

12.30-13.00

12.30-13.00

Summary &

Closing 12.45-13.00

DC 2013-4 A. Comisso

13.00-15.00

Registration & Lunch

13.00-15.00

Lunch 13.00-15.00

Lunch 13.00-15.00

Lunch 13.00-15.00

Lunch

15.00-15.15

Opening 15.00-15.45


IP -4

P.Wachulak

15.00-15.30

Associated Partner DESY

M.Meyer

15.00-17.00

Laboratory Tour /

Executive Management Committee

Meeting

Departure

15.15-16.00


IP -1

K. Kozak

15.30-16.00

Associated Partner ITME

L. Dobrzański 15.45-16.00

DC 2013- 5 H. Lu

16.00-16.30

DC 2012-1

I.U.Ahad

16.00-16.15

DC 2013-6

M. Odstracil

16.00-16.30

Associated Partner

M. Regehly 16.15-

16.30 DC 2013-7

R. Lokasani

16.30-17.00

Coffee Break

16.30-17.00

Coffee Break

16.30-17.00

Coffee Break

17.00-17.30

DC 2012-2

D.Adjei

17.00-17.15

DC 2013-8

M. Miszczak

17.00-17.30

Associated Partner

RIGAKU L.Pina 17.15-

17.30 DC 2013-9 S.J. Davitt

17.30-18.00

DC 2012-3

H. Kim

17.30-17.45

DC 2013-10 W. Hanks

17.30-18.00

18.00-20.00

Reception 18.00-20.00

Dinner

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Invited presentations

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IP -1

Synchrotron radiation - selected application in biology

Maciej Kozak

Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University,

Poznan, Poland.,

E-mail: [email protected]

The first experiment, which demonstrated the generation of synchrotron radiation by the use

of the small laboratory synchrotron, was carried out over 60 years ago in a group of Pollock

[1]. The next decades brought significant technological development in the field of generation

of synchrotron radiation. However, the rapid increase in the use of synchrotron radiation in

biology we observe since the 80’s of the last century [2].

At the moment, the leading areas of science, for which synchrotron radiation is the primary

research tool are structural biology and protein crystallography [3,4]. Today, more than 200

research stations in the synchrotrons worldwide can be used to study the structure of

biological samples.

During the lecture will be introduced basic information on synchrotron radiation and the

technical requirements for beam lines dedicated biological measurements [5]. The

presentation will be illustrated by some exemplary results of structural studies of proteins,

nucleic acids, lipid nanosystems, cell organelles or tissues [6-9].

References

[1] F.R. Elder, A.M. Gurewitsch, R.V. Langmuir, H.C. Pollock, Phys. Rev. 71 (1947) 829

830.

[2] M. Jaskolski, Z. Dauter, A. Wlodawer, FEBS Journal 281 (2014) 3985-4009.

[3] S. Skou, R.E. Gillilan, N. Ando, Nat. Protoc. 9 (2014) 1727-1739.

[4] I. Schlichting, J. Miao, Curr. Opin. Struct. Biol. 22 (2012) 613-626.

[5] E. Abola, P. Kuhn, T. Earnest, R.C. Stevens, Nature Struct. Biol. 7 (2000) 973-977

(Suppl.).

[6] A. Yonath, J. Royal Sci. Interface 6 (2009) S575-S585.

[7] M. Jaskolski, Acta Phys. Polon. A 117 (2010) 257-263.

[8] M. Kozak (2007). in: CP958, Nucl. Phys. Meth. Acceler. in Biol. and Med., (Ed. C.

Grranja, C. Leroy, and I. Stekl) AIP 978-0-7354-0472-4/07 (2007) pp. 178-182.

[9] C.A. Neldam, E.M. Pinholt, J. Cranio-Maxillofacial Surg. 42 (2014) 801-805.

mailto:[email protected]

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IP -2

X-ray free electron lasers and applications.

Ryszard Sobierajski

Institute of Physics Polish Academy of Science, Warsaw, Poland


Interaction of intense ultrashort extreme ultraviolet (XUV) and soft x-ray pulses with solid

matter will be described. The presentation is related to the development of presently most

sophisticated 4th generation synchrotron radiation sources - the short-wavelength free

electron lasers (FELs). With the advent of the sources, a unique combination of radiation

properties creates new research possibilities. In particular, radiation intensity produced in

FELs, by many orders of magnitude exceeds intensities available from other monochromatic

XUV and x-ray sources, making thus it possible to excite a solid material through phase

transition points. Thank to this a systematic studies of structural changes in materials and

electronic properties, as well as transition dynamics and energy transfer processes are

possible. As typical pulse duration, on the order of femtoseconds, is shorter than most of the

time constants related to structural transformations and to the energy transfer, it is possible to

separate the processes from influence of radiation absorption during the pulse duration.

Moreover, the photon energies, larger than value of energy gap in any material makes it

possible to avoid nonlinearities in absorption what radically simplifies the modeling of the

subsequent physical processes. However, properties of the intense FEL beam create, apart

new experimental opportunities, the extreme demands to optical elements applied in the

experimental equipment. Amongst the most serious issues is radiation load imposed on

detectors and to most of optical elements served for beam diagnostics, controlling and

shaping. For the above reasons, bulk silicon and nanolayers - materials applied in optical and

detection systems with intense short-wavelength beams - are of a particular interest.

Short introduction to the FEL sources will be presented. It will be followed by results of the

recent experimental work at three FEL facilities – FLASH in Germany, LCLS in US and

SACLA in Japan. Structural changes in bulk silicon, single- (a-C, B4C) and multilayer

(Mo/Si, MoNSiN) coatings under single shot irradiation will be described. In specific cases

they will be compared to the results of the irradiations with nanosecond pulses from table-top

plasma sources. Experimental damage threshold will be explained with simple theory.

Acknowledgments:

This work was supported by the Polish National Science Center (Grant No. DEC-

2011/03/B/ST3/02453).


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IP-3

X-ray microprobe in radiobiology studies

Janusz Lekki

Institute of Nuclear Physics PAN, Cracow, Poland


Radiation microprobes established new standard in radiobiology studies and have great

impact in a recent rapid increase in knowledge of biological pathways and the

physical/chemical processes occurring during radiation induced damage of cells and

their subsequent repair or elimination. Chronologically, mainly ion microprobes were used

to investigate cell response as a function of a precisely delivered radiation dose, counting the

numbers of apoptotic cells, irradiated cells forming micronuclei and surviving cells with

chromosome aberrations. Perhaps the most striking impact is related to experiments showing

non-targeted effects, when radiation induced damage is observed in some non-irradiated cells

in the vicinity of irradiated ones. Clinical medicine could vastly profit from the progress in

reliable knowledge about radiation induced non targeted effects. Another, vividly discussed

issue is the postulated existence of thresholds in the dose-response characteristics of the

biological system: at certain dose and dose rate levels, saturation of the repair centre

mechanism occurs and, at higher doses, a new repair mechanism emerges. If the threshold

concept is validated, such findings could have large impact in radiation protection and

microdosimetry.

It was however very clear from the beginning that the biological endpoints of radiation

damage depend not only on radiation dose, but also on the radiation quality – especially on

the density of ionization events and hence on the value of Linear Energy Transfer (LET).

Experiments performed with targeted light ions have subsequently been extended to heavier

ions of different energy, electron beams, gamma and X-rays, and UV radiation. In this

spectrum, X-ray microprobe is a tool delivering low-LET (< 1 keV/µm) radiation of sparse

ionization, causing scattered effects distributed in the whole volume. In spite of the fact that,

finally, it’s ionisation of the organic matter that is responsible for radiation damage, the above

mentioned features of X-ray radiation make it a very distinctive tool, delivering data

complementary to ion irradiation results.

The first construction of this type was the Gray Cancer Institute microprobe, delivering soft

radiation (carbon K line of 278 eV), focused with the Fresnel zone plate. Currently, several

groups develop different types of X–ray microprobes in wide range of X–ray energies – both

as standalone laboratory devices and setups at the synchrotron radiation facilities. In the

lecture, the short overview of current X-ray microprobe constructions will be shown, with the

special emphasis of the IFJ PAN design. Parallel to microprobe issues presentation, main

concepts of the targeted X-ray radiobiological experiments (already performed or eventually

possible) and the expected findings will be discussed.


13

IP -4

Nanoimaging using soft X-ray and EUV sources

Przemysław Wachulak

Institute of Optoelectronics, Military University of Technology, Warsaw, Poland


Visualizing small objects in the nano-meter scale with high spatial resolution is very

important from the point of view of modern science and technology. To extend the diffraction

limit associated with the wavelength of radiation, one way is to reduce the wavelength,

allowing smaller features to be resolved.

This requires short wavelength sources, capable of delivering sufficient flux to achieve high

signal-to-noise ratio images. Those sources are synchrotrons, free electron lasers, but also

compact sources, such as laser-plasma, discharge-pumped, or high harmonic generation

sources plasma, among others.

The goal of achieving nanometre spatial resolution cannot be accomplished without

specialized optics, often dedicated for specific spectral range, mostly reflective and

diffractive, sometimes refractive optics for keV-range photon energies. Moreover, many

unique imaging techniques were also developed and will be mentioned in the presentation,

including: holography, Talbot imaging, diffraction (lensless) imaging, zone plate based

imaging, scanning microscopy, contact microscopy and tomography.

Of course this brief lecture cannot address all available possibilities to achieve nanoscale

imaging, however, it might be a good introduction to this innteresting and novel topic.


14

IP -5

X-ray crystal optics and spectroscopy

Eckhart Förster

Institute of Optics and Quantum Electronics, Friedrich Schiller University, Jena

and Helmholtz Institute Jena, Jena, Germany


Much effort has been given both in development of modern dedicated synchrotrons and free

electron lasers with unique properties. Also, femtosecond laser plasma sources provide ultra-

short x-ray pulses of high peak brilliance and can thus be complementary x-ray sources to the

undulator based sources. All these modern x-ray sources need dedicated x-ray optics for

diagnostics and applications, respectively. An overview about different schemes of x-ray

optics will be given; these optic instruments differ in efficiency, spectral selectivity, and

focusing ability. Many x-ray experiments require either high-efficient point-to-point imaging

in narrow spectral channels or high spectral resolution, sometimes combined with 1-D spatial

resolution, perpendicular to the dispersion plane.

In order to fulfill all the different demands of these x-ray diagnostic or real-time application

experiments, our x-ray crystal optics have been designed by using ray-tracing and Bragg

reflection codes for the 1D or 2D bent crystals or combinations thereof. Selection of the bent

crystal spectrometers starts from values of wavelength (0.01 nm - 3 nm), curvature (radii: 50

mm - 2 m) and imaging parameters (1 - 30). In the preparation process, extreme care has been

set value on crystal perfection, selection of optimal reflections, precision bending, and

measurement of x-ray imaging and reflection properties. High resolution have been obtained

when structurally perfect wafers of Si, Ge, Quartz and Phthalate crystals are prepared whilst

monitored by x-ray topography and diffractometry.


15

IP -6

Interaction of intense extreme ultraviolet and X-ray radiation with matter

Libor Juha

Department of Radiation and Chemical Physics, Institute of Physics ASC, Prague, Czech Rep.


Interaction of extreme ultraviolet radiation (EUV or XUV; 10 nm < < 100 nm), soft x-rays

(SXR; 0.2 nm < < 30 nm) and x-rays (< 0.2 nm) with matter differs dramatically from that

of the long-wavelength (i.e., UV-Vis-IR) radiation. The interaction of the short-wavelength

radiation occurs mostly due to the photo-effect in atoms of the irradiated material. Valence

electrons play in general a minor role in the interaction. Thus an absorption coefficient

depends mostly on the elemental composition and density of the irradiated material. Contrary

to the long-wavelength radiation, there is a little influence of the fine chemical structure of the

particular material chosen for an irradiation.

In addition to that, the short-wavelength radiation is deposited much effectively in the

material because an effect of plasma reflection of laser light is reduced. It follows from the

fact that in a certain spatial position in the plasma, where the oscillation frequency of plasma

electrons (so called plasma frequency and/or Langmuir frequency) oscillating in the

electromagnetic field is equal to the frequency of laser radiation, the index of refraction

becomes zero and the electromagnetic wave is reflected. Langmuir frequency is a function of

electron density (ne): e2 = ne e

2 / 0 me . Laser frequency is equal to the Langmuir frequency

at the critical density which depends on the laser wavelength in the following way: nc

[electrons in cm3] = 10

21 x

-2 [m]. Let compare a typical EUV and VUV laser from this

point of view. A critical electron density nc = 5x1023

cm-3

can be expected for 46.9-nm

radiation in the EUV spectral range. It means that the EUV-laser radiation can penetrate all

the parts of the plasma formation volume with an electron density < 5x1023

cm-3

. This value is

comparable to an electron density of solids. Therefore the sample can be heated by the short-

wavelength radiation in the whole volume irradiated. Thus the technique is called a

volumetric heating. In comparison, the critical density is at least 15x smaller for ArF excimer

laser. Expanding ArF-laser-induced plasma plume begins to reflect the 193-nm laser radiation

at a certain moment of the interaction course.

Currently, we may identify at least six strong sources of motivation to conduct systematic

study in the field of interaction of intense short-wavelength electromagnetic interaction with

matter: (a) Estimating and minimizing damages to surfaces of highly irradiated EUV/x-ray

optical elements developed and used for the guiding and focusing of short-wavelength laser

beams as well as those used for long-term irradiation with high repetition rate sources, (b)

durability assessments of materials suggested for the first walls of ICF reactors and optical

elements exposed to intense EUV/x-ray radiation in a laser-plasma interaction chamber, (c)

diffraction-limited ultrastructuring and patterning of solid surfaces for fabrication of

microelectronic and micromechanical elements and devices, (d) pump-and-probe, imaging

and high-dose-rate irradiations in radiation chemistry, radiobiology, and other scientific and

technological applications of high-power short-wavelength sources, (e) determination of

radiation field characteristics: imaging of spatial energy distribution in a focused beam

ablatively imprinted on the irradiated material and determination of pulse energy content, and

(f) production of very dense plasmas with low electron temperatures, i.e., warm dense matter

(WDM). In this contribution, specific features of the intense short-wavelength radiation-

matter interaction will be discussed with respect to the above-mentioned applications.


16

IP -7

Plasmonic nanostructures for applications in surface enhanced

spectroscopies, photocatalysis and photovoltaics

Bartłomiej Jankiewicz, Magdalena Gajda-Rączka, Bartosz Bartosewicz, Paulina Dobrowolska



Plasmonic nanostructures, in form of noble metal colloids, hybrid nanostructures and thin

films, have a great potential for various applications due to their unique optical properties.

These materials exhibit surface plasmon resonance at certain wavelengths and accumulate

energy of electromagnetic field in nanosize regions called hot spots. The spectral position of

resonances is dependent on geometry of nanostructures and types of materials they are made

of. Plasmonic nanostructures are investigated for many applications including surfaced

enhanced spectroscopies such as Raman spectroscopy (SERS) [1,2], IR spectroscopy

(SEIRA) [1,2] or fluorescence spectroscopy (SEF) [3], cancer therapy [4], as well as

photovoltaics and photocatalysis.

We report here results of investigations on fabrication, characterization and applications of

various plasmonic nanostructures based on the noble metals (gold, silver), silica and titania

(including those shown below) fabricated using chemical methods. The results presented here

are effect of the research projects, which have been carried out in the Nanoplasmonic

Laboratory of IOE MUT for the last three years.

Acknowledgments

This work is supported by The National Centre for Research and Development, Grant No. O

N507 282540, the National Science Centre, Grant No. 2011/03/D/ST5/06038. This work was

also funded under grant A-1152-RT-GP “RAMBO” carried out in the frame of the EDA JIP

on CBRN protection.

References

[1] Le, F., Brandl, D. W. Urzhumov, Y. A., Wang, H., Kundu, J., Halas, N. J. Aizpurua, J.,

Nordlander, P. ACS Nano 2, 707-718 (2008).

[2] Levin, C. S., Kundu, J., Barhoumi, A., Halas, N. J. Analyst, 134, 1745-1750 (2009),

[3] Fort, E., Grésillon, S. J. Phys. D: Appl. Phys. 41, 013001, (2008)

[4] Lin, A. W. H, Lewinski, N. A., West, J. L., Halas, N. J., Drezek, R. A. J. Biomed. Opt.

10, 064035-1 (2005).


17

IP -8

Detectors of THz radiation based on FETs

Przemysław Zagrajek



Terahertz radiation is a part of electromagnetic spectrum located between millimeter and

infrared waves. It has features interesting for various disciplines, e.g. surveillance (high

transmittance through clothing and packing materials, fingerprints of explosive materials),

medicine (imaging of diseased tissue), telecommunication (possibility of high speed

communication due to high bandwidth).

Development of applications still suffers from a lack of sensitive, compact and chip detectors.

One of the candidates, which are intensively investigated, are devices based on transistors.

According to the theory proposed by Dyakonov and Shur, it is possible to detect THz

radiation by Field Effect Transistors. Due to the plasma oscillations in the conduction channel

such kind of the detector is able to work with frequencies much higher than cut-off frequency

of the transistor. Detection proces was observed in High Electron Mobility Transistors as well

as in silicon MOSFETs.

Parameters of the detector like responsivity, frequency dependence, response time are

measured during characterization process.


18

EXTATIC Partners

Presentations

19

PP -1

Research facilities and programmes at DCU and internationally

John T. Costello (on behalf of the DCU partners and collaborators)

School of Physical Sciences & NCPST: Dublin City University, Dublin 9, Ireland


At DCU we are mainly focused on the interaction of intense laser beams with matter.

Specifically we are interested in laser plasma generation, diagnostics and application in areas

such as pulse laser deposition (PLD), laser induced breakdown spectroscopy (LIBS),

Vacuum-UV (VUV) and Extreme-UV (XUV) light sources for photoionization of atoms and

ions in plasma plumes. Although much of our focus is on optical diagnostics from the Vis/UV

to the XUV range we are also growing our interest in particle (specifically ion) diagnostics.

The main staff involved are Eugene Kennedy (Professor Emeritus), Paddy Hayden (SFI SIRG

PI), Jean-Paul Mosnier (Senior Faculty), Mossy Kelly (PD Fellow), Pramod Pandey (PD

Fellow) and Colm Fallon (PD Fellow) with 8 research students on site and 2 incoming.

Away from DCU we are working in international collaborations on photoionization processes

in atoms and molecules at synchrotrons such as SOLEIL (Orsay, France) and XUV/X-ray free

electrons lasers (FELs) such as FLASH-Hamburg, LCLS-Stanford and FERMI@ELETTRA-

Trieste. The main experimental collaborators here are Jean-Marc Bizau (Orsay), Michael

Meyer (XFEL GmbH), Reinhard Kienberger (MPQ-Garching) and Adrian Cavalieri (CFEL-

Hamburg). Currently the main PD Fellow from our side is Mossy Kelly. Theoretical work is

led by Lampros Nikolopoulos both at DCU and in the frame of international collaborations.

The short talk will introduce the current facilities/programmes and those in planning/

development. Some illustrative published work from DCU and internationally includes:

Dichroism in the above-threshold two-colour photoionization of singly charged neon

V Richardson et al., J. Phys. B: At. Mol. Opt. Phys. 45 085601 (2012)

Ultrafast X-ray pulse temporal characterization for free-electron lasers

I Grguras et al., Nature Photonics 6 852-857 (2012)

Atomic mass dependent electrostatic diagnostics of colliding copper laser plasma plumes

P Yeates, C Fallon, E T Kennedy and J T Costello, Physics of Plasmas 20, 093106 (2013)

Dual-pulse laser induced breakdown spectroscopy with ambient gas in the vacuum ultraviolet:

optimization of parameters for detection of carbon and sulphur in steel

X Jiang, P Hayden, J T Costello and E T Kennedy, Spectrochimica Acta Part B: Atomic Spectroscopy

901 106-113 (2014)

Determining the polarization state of an extreme ultraviolet free-electron laser beam using atomic

circular dichroism

T Mazza et al., Nature Communications 5, 3628 (2014)


20

PP -2

EUV applications at RWTH Aachen

S. Danylyuk1, L. Juschkin

2

1Chair for Technology of Optical Systems, RWTH Aachen University

2Chair for the Experimental Physics of EUV, RWTH Aachen University

Email: [email protected]

The presentation will introduce a spectrum of EUV-related activites at the RWTH Aachen

university. Emphasis will be made on EUV metrology applications, such as EUV

reflectometry and defect inspecion, as well as on EUV interference lithography and proximity

printing activities. Emerging activities on EUV coherence diffraction imaging and tabletop

EUV magnetic circular dichroism imaging that can be of interest for EXTATIC community

will be also presented. Potential and perspectives of the laboratory based EUV/Soft-X-ray

applications will be discussed.


21

PP -3

Research of plasmas produced by intense laser pulses and by capillary

discharges at FNSPE CTU in Prague

J. Limpouch, A. Jančárek, P. Gavrilov, L. Pína

1Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical

Engineering, Prague, Czech Republic


We shall briefly introduce Czech Technical University in Prague together with our faculty

and with our Department of Physical Electronics. Research in the fields concerning

EXTATIC is performed in the laboratory of capillary discharges, in the laboratory of

femtosecond laser and in collaborating laboratories of other institutions.

Our capillary discharge installations will be described in detail. Our capillaries are filled

either by argon or nitrogen. Lasing in collisionally pumped argon at wavelength 46.9 nm was

demonstrated. Attempts to achieve lasing via recombination scheme in nitrogen have not been

successful yet due to stringent requirements on the high-voltage source. Capillary discharge

serves also as intense source of incoherent XUV radiation with various possible applications.

EUV radiation of argon laser was focused by symmetric ellipsoidal optics in order to enhance

radiation intensity.

Our laboratory of 10 mJ, 60 fs, 10 Hz Ti: Sapphire laser will be presented. Our laser is used

for surface modifications of various materials, for generation of XUV radiation in various

targets and also for some non-linear optics experiments. Our department has also capability to

prepare targets with various nanostructured surfaces. We are also collaborating in experiments

at PALS laboratory equipped with kJ-class subnanosecond iodine laser and 25-TW

femtosecond Ti-sapphire laser. Our groups has also vast expertize in fluid and PIC numerical

simulations of plasma dynamics.


22

PP -4

EUV optics research at Padova

P. Nicolosi

Dept. Of Information Engineering, Univ. of Padova and IFN CNR UOS Padova


EUV Optics research carried on at Department of Information Engineering of University of

Padova and at LUXOR UOS of Padova Institute of Photonics and Nanotechnolgy CNR will

be presented. Emphasis will be made on Multilayer optics development, SPACE

instrumentation, Synchrotron and FEL instrumentation and optics for industrial applications.


23

PP -5

Laser plasma sources of soft X-rays and extreme ultraviolet (EUV)

for application in science and technology

H. Fiedorowicz, A. Bartnik, R. Jarocki, J. Kostecki, M. Szczurek, P.W. Wachulak

D. Adjei, I.U. Ahad, M.G. Ayele, T. Fok, A. Szczurek, A. Torrisi, Ł. Węgrzyński



The Institute of Optoelectronics (IOE) (www.ioe.wat.edu.pl) is an interdisciplinary academic

research institute at Military University of Technology (MUT) with a mission to support

research and education in optoelectronics and lasers. The research staff of 180, including 100

scientists and 60 engineers and technicians, pursues numerous research projects funded by the

government or industry. IOE is a leading research institution on laser development and

application in Poland. The specific areas of research activities in the field include: laser optics

and electronics, laser systems, laser-matter interactions, laser cleaning, laser nanotechnology,

laser ranging and sensing.

The Laser-Matter Interaction (LMI) research group (www.ztl.wat.edu.pl/zoplzm) participating

in the EXTATIC programme is specializing in development of laser-driven X-ray and EUV

sources and their applications in science and technology. The sources are based on a gas puff

target approach. The gas puff targets formed by pulsed injection of a small amount of gas

under high-pressure are irradiated with nanosecond laser pulses from commercial Nd:YAG

lasers. We use lasers generating pulses with time duration from 1ns to 10ns and energies from

0.5J to 10J at 10Hz repetition rate. The targets are produced with the use of a valve system

equipped with a special nozzle to form a double-stream gas puff target which secures high

conversion efficiency without degradation of the nozzle and production of target debris. The

sources are equipped with optical systems to collect soft X-rays and EUV radiation and form

the radiation beam, including grazing incidence axisymmetrical ellipsoid mirrors, a “lobster

eye” type grazing incidence multi-foil mirror, and an ellipsoidal mirror with Mo/Si multilayer

coating. The EUV source with the grazing incidence ellipsoid mirror is used for processing of

materials by direct EUV photo-etching. Efficient micro- and nanoprocessing of various

polymers was demonstrated. EUV modification of polymer surfaces for biocompatibility

control is studied under the EXTATIC project. The source with the ellipsoidal mirror with

Mo/Si multilayer coating has been used for imaging with nanometer resolution using a

Fresnel zone plate as the objective. EUV imaging with the spatial resolution of about 50nm

has been demonstrated. The source with the grazing incidence ellipsoid mirror as the

condenser and the grazing incidence hyperboloid/ellipsoid (Wolter I type) mirror as the

objective was used for imaging in the “water window” wavelength range with sub-micrometer

resolution. Nanoimaging with soft X-ray and EUV photons will be studied under the

EXTATIC project. Laser plasma soft X-ray sources for application in radiobiology and

contact microscopy are developed under the EXTATIC projects. The EUV sources are also

used in research on photoionization processes of gases injected into the interaction region and

creation of a photoionized plasma. Spectra in the EUV/VUV region from photoionized

plasmas are measured using a grazing incidence, flat-field spectrometer. The EXTATIC

project on this subject has been proposed. The LMI group poses also a 10TW femtosecond

laser system to be used in the experiments on generation of ultra-short X-ray pulses and high-

order harmonic generation (HHG).


http://www.ioe.wat.edu.pl/

http://www.ztl.wat.edu.pl/zoplzm

24

PP- 6

Atomic, Molecular and plasma physics at UCD

Tom McCormack*

1University College Dublin,Dublin, Ireland

The Atomic, Molecular and Plasma Physics Group at the School of Physics is a world leader

in soft x-ray and EUV physics and technology. We have developed a world class set of

experimental, computational and modelling laboratories. Our lab space, of over 400 square

metres, includes an array of photon spectrometers from the x-ray to the infra-red, an

electrostatic ion spectrometer, a photoelectron spectrometer and lasers that allow us to explore

a vast range of plasma parameters and examine them over a range of spectral, spatial and

temporal resolutions, unique in a university lab in the world. The School of Physics enjoys the

support of electrical and mechanical workshops (4.5 staff) that are essential for experimental

research projects.

The group currently consists of 5 academics, 3 postdoctoral researchers and 8 PhD students.

It collaborates with researchers at Utsunomiya University, The Japanese National Instiute for

Fusion Science, ILE Osaka, Tokyo Metropolitan University, NIST, JILA, Berkeley and

Lanzhou. The Group has made a major contribution to the development of EUV Lithography

light sources for semiconductor lithography. Over the last 6 years the group has received over

€5 million in research awards. These awards have covered the full gamut of research projects

looking at fundamental physics in plasmas and EUV/soft x-ray spectroscopy, to applied

research awards. We have also received substantial industrial funding and have begun

commercialiation of our research through our spin-out company NewLambda Technologies

Ltd (http://newlambda.com).

25

EXTATIC Associated Partners

Presentations

26

AP -1

Investigations of atomic and molecular photoionization dynamics

at short-wavelength Free-Electron Lasers

M. Meyer1, T. Mazza

1, A. DeFanis

1, M. Ilchen

1, M. Kelly

2, J.T. Costello

2, P. O’Keeffe

3,

P. Lambropoulos4, N. Kabachnik

1,5 and A. Kazansky

5

1European XFEL GmbH, Hamburg, Germany

2Dublin City University: School of Physical Science and NCPST, Dublin, Irland

3CNR: Instituto di Struttura della Materia, Monterotondo Scalo, Italy

4IESL-FORTH and University of Crete:Physics Department, Heraklion, Greece

5Donostia International Physics Center, San Sebastian, Spain

E-mail:[email protected]

The unprecedented characteristics of new XUV and X-ray Free Electron Lasers, such as

FLASH, FERMI and LCLS, have stimulated numerous investigations focusing on the detailed

understanding of fundamental photon-matter interactions in atoms and molecules. In

particular, the effect of high intensities (up to 1016

W/cm2) giving rise to multiple ionization

processes as well as the temporal evolution of ultra-fast photo-induced processes (down to a

few 10-15

s) can be studied for the first time in the short wavelength regime, i.e. at photon

energies high enough to excite and to interact with strongly bound core electrons.

In recent experiments, the high intensites of the XUX-FEL pulses were used to study multiple

ionization of Ar and Xe atoms as well as to explore multi-photon processes such as sequential

ionization and above-threshold ionization. These experiments serve as case studies for the

non-linear response of matter to short wavelength radiation and, in particular, allow for a

critical comparison with theoretical predictions for this type of processes. For atomic Ar

ionized at 105 eV photon energy, the study reveals e.g. the importance of strong electron

correlations, in particular the decisive role of shake-up and shake-off processes for the

interpretation of the observed high charge states, i.e. up to Ar7+

[1].

For time-resolved two-color experiments, the combination with an intense, synchronized

optical laser is enabling studies of photoionization dynamics in the presence of strong optical

fields, such as the modification of the angle-resolved photoelectron and Auger spectra, which

reveal strong intensity modulations induced by sub-cycle interferences. The use of circularly

polarized FEL light, recently available at FERMI, provides insight into dichroic phenomena.

In a first application, we have demonstrated how dichroism is induced and afterwards probed

in an intially unpolarized He target. The measurement of circular dichroism enables in

addition the characterization of the polarizationproperties of XUV FEL beams in an elegant,

non-invasive andstraightforward fashion [2].

After these illustrating examples, future opportunities opened up with the start of operation of

the European XFEL at the end of 2015 will be presented. Special focus will be given to one of

the six permanent experimental stations, the SQS (Small Quantum System) Scientific

Instrument, which is dedicated to the investigation of atoms, ions, molecules and clusters in

intense fields and to the study of non-linear phenomena [3].

References

[1] M. Ilchen et al., submitted to Phys. Rev. Lett. (2014)

[2] T. Mazza et al., Nat. Commun. 5:3648 doi: 10.1038/ncomms4648 (2014)

[3] http://www.xfel.eu/documents/technical_documents


http://www.xfel.eu/documents/technical_documents

27

AP -2

Photodetectors and diffractive optics at ITME

Lech Dobrzański

Institute of Electronic Materials Technology, Warsaw, Poland


We developed UV detectors on basis of the GaN/AlGaN hetrostructure. Detectors of the

Schottky type - visible and solar blind cover the UVA, UVB and UVC range. The unique UV

detectors are of the p-i-n type which exhibit banpass spectral sensivity characteristics. We can

control detector band position and band witdth and analyse some specific emission

sources.The MSM photodetectors for UV have been developed as well.

We will present some realizations of fast photodetectors on basis of InP, GaAs and SiC

designed for sensing of short light pulses.

Moreover, we have 20 years of experience in direct e-bem writing and subsequent rective ion

etching of substrates. These technologies enable realization of diffractive optical elements.

We realized DOEs for infrared and visible spectral range. Now we can extend our activity to

UV range, because we invested in the new e-beam writer. The smallest feature size we can

expose and etch is 50nm. The examles of developed devices and lenses will be presented, as

well as some application of these products in more complex systems.


28

AP -3

Low readout-noise CCD-cameras for UV, VUV, EUV and X-ray imaging

and spectroscopy

Martin Regehly

greateyes GmbH, Berlin, Germany

E-mail: mailto:[email protected]

For the simultaneous measurement of space- and frequency-resolved light signals, CCD

sensors based cameras achieve currently the highest sensitivity and dynamics. For the

detection of weak light signals an important eligibility criteria is, besides a high sensitivity in

the respective spectral range, an acquirable signal-to-noise ratio (SNR). In this presentation

the noise processes which are involved in measurements and their influence on the SNR are

discussed based on the fundamental functionality of CCD sensors and camera electronics.

Besides that detectors for the measurement of weak light signals in the spectral range of UV,

VUV, EUV and X-Ray are presented. The CCD cameras combine scientific CCD sensors

with ultra low noise electronics for optimal detection of weak signals.


29

AP -4

30

EXTATIC Doctoral Candidates

Presentations

31

DC 12-1

Extreme ultraviolet surface modification of polymers for biomedical

engineering applications

Inam Ul Ahad

1,2, Beata Butruk

3, Bogusław Budner

1, Tomasz Jan Kaldonski

4, Andrzej

Bartnik1, Henryk Fiedorowicz

1, Tomasz Ciach

3 and Dermot Brabazon

2

1Institute of Optoelectronics, Military University of Technology, Warsaw, Poland 2

Advanced Processing Technology Research Centre, School of Mechanical and

Manufacturing Engineering, Faculty of Engineering & Computing, Dublin City University,

Dublin 9, Ireland 3Department of Biotechnology and Bioprocess Engineering, Warsaw University of

Technology, Warsaw, Poland 4Faculty of Mechanical Engineering, Military University of Technology, Warsaw, Poland


Tuning of polymer surface properties is often desirable for various applications in bio-

implants, artificial muscles and diagnostic devices. Surface properties can be modified by

fabrication of micro- and nano-structures on their surfaces by direct-photo etching technique

using ultraviolet irradation. However degradation of bulk material is reported which is

undesirable in biomedical engineering applications. This limitation can be avoided by using

short wavelength radiation in the extreme ultraviolet (EUV) range that is absorbed in very

thin (less than 100 nm) layer of the polymer. EUV photons can be produced by synchrotron

radiation (SR) sources or laser-plasma sources. The limited number and accessibility to large

scale SR facilities encouraged the development of compact laboratory scale EUV sources.

Polytetrafluoroethylene (PTFE) is widely used for fabrication of vascular prostheses and

tubes for nerve regeneration. The associated challenges of PTFE, such as the low free surface

energy, thrombogenic surface and low wear resistance can be overcome by surface

modification.

In this study, PTFE samples were irradiated with a laser-plasma EUV source. The source is

based on a double-stream gas-puff target, irradiated with a 3 ns/0.8J Nd:YAG laser pulse at

10Hz. Using a gold-plated grazing incidence ellipsoidal collector, an effective EUV radiation

at the wavelength centred about 11 nm is focused at 0.5 mm spot. The source is equipped with

an auxiliary gas-puff valve to inject nitrogen gas into the EUV – sample interaction region in

order to change chemical composition. The physical and chemical properties of irradiated

samples were characterized by scanning electron microscopy (SEM), atomic force

microscopy (AFM), water contact angle (WCA) measurements, and x-ray photoelectron

spectroscopy (XPS) respectively. Pronounced wall type structures appeared on the surfaces of

polymers which provide focal adhesion points for better cell adhesion. The surface roughness

increased up to many folds and increment in WCA (up to 20º) observed. The elemental

analysis by XPS showed deposition of nitrogen atoms on upper layer surface of EUV

modified polymers. In-vitro cell culture studies, using L929 mouse fibroblasts demonstrated

strong cell adhesion and increased cell viability in EUV modified PTFE samples as compared

to pristine control sample.

Acknowledgements.

The authors acknowledge financial support from the EU FP7 Erasmus Mundus Joint

Doctorate Program EXTATIC under framework partnership agreement FPA-2012-0033 and

from the 7th Framework Programme's Laserlab Europe project (No. 284464).


32

DC 12-2

Development and application of a compact laser-produced plasma

soft X-Ray source for radiobiology experiments

Daniel Adjei1, Mesfin Getachew Ayele

1, Przemysław Wachulak

1, Andrzej Bartnik

1,

Luděk Vyšín2, Libor Juha

2, Henryk Fiedorowicz

1, Łukasz Wegrzynski

1, Anna Wiechec

3,

Janusz Lekki3, Wojciech M. Kwiatek

3

1Institute of Optoelectronics, Military University of Technology,Warsaw, Poland

2Institute of Physics Czech Academy of Sciences, Prague, Czech Republic

3Institute of Nuclear Physics Polish Academy of Sciences, Cracow, Poland


A desk-top laser produced plasma source of soft X-rays has been developed for radiobiology

research. The source is based on a double-stream gas puff target irradiated with a commercial

Nd:YAG laser. The source has been optimized for maximum emission in the X-ray “water

window” spectral wavelength range from 2.3 nm to 4.4 nm wavelength (280 - 540 eV) by

using argon gas puff target and spectral filtering. The source delivers nanosecond pulses of

soft X-rays with fluence of about 4.20x103 photon/µm2/pulse at a sample placed inside the

vacuum chamber and about 7.48x102 photon/µm2/pulse at a sample outside the chamber.

The design and characterization measurements of the source will be discussed. The source has

been used for the first time in radiobiology experiments. Remarkable strand breaks were

observed in irradiated supercoiled plasmid pBR322 DNA by gel electrophoresis and the

results will be presented. The source can be useful in addressing observations related to

cellular sensitivity to “water window” X-ray spectral range.

Acknowledgments

The authors acknowledge the financial support from the EU FP7 Erasmus Mundus Joint

Doctorate Programme EXTATIC under framework partnership agreement FPA-2012-0033.

With the support from the 7th Framework Programme’s Laserlab Europe project (No.

284464). PW greatly acknowledges the support by the National Centre for Science, award

number DEC-2011/03/D/ST2/00296 and the National Centre for Research and Development,

Lider programme, award number LIDER/004/410/L-4/12/NCBR/2013.


33

DC 12-3

EUV interference lithography with fractional Talbot effect

Hyun-su Kim1, 3

, Serhiy Danylyuk2, Sascha Brose

2, Wei Li

4, Mario C. Marconi

4,

William S. Brocklesby3, Larissa Juschkin

1

1 Chair for the Experimental Physics of EUV, RWTH Aachen University and JARA –

Fundamentals of Future Information Technology, Aachen, Germany 2 Chair for the Technology of Optical Systems, RWTH Aachen University and JARA -

Fundamentals of Future Information Technology, Aachen, Germany 3 Optoelectronics Research Center, University of Southampton, Southampton, UK

4 Engineering Research Center for Extreme Ultraviolet Science and Technology, and

Electrical and Computer Engineering Department, Colorado State University,

Fort Collins,USA


Extreme ultraviolet (EUV, spectral range below DUV and above soft X-ray) interference

lithography is a powerful method of fabricating sub-micron structures for many applications

such as semiconductor devices, plasmonics, photonic crystals, quantum dots, etc. Talbot

lithography is a mask-based interference lithography technique using Talbot effect that

produces a replicating pattern in the near field of a periodic mask illuminated with coherent

plane wave, which can produce very fine detail.

In this work we demonstrate the Talbot lithography with fractional Talbot effect under highly

coherent EUV light of 46.9 nm wavelength generated by a capillary discharge Ne-like Ar

laser in order to achieve high special frequency multiplication more than 2x. A transmissive

diffraction grating or Talbot mask, defined directly into a gold deposited Si3N4 membrane by

focused ion beam milling, is illuminated under the EUV. The fractional patterns form through

the space behind the mask as a function of Talbot distance from the mask. As a result, various

spatial frequency multiplications, Msf = up to 5x are achieved from one parent mask.

Sampled patterns are compared to theoretical predictions of the pattern, and good agreement

is seen.

We envision that the grating with the smaller pitch size could be used for further reduction as

well as the grating with narrower slit could be used to get higher Msf values, more than Msf =

5x. Also the utilization of recently developed EUV lasers in the vicinity of 13 nm can further

decrease the feature size achievable with this patterning approach.


34

DC 12-4

Sn Based Laser Assisted Vacuum Arc EUV Source

Girum Abebe Beyene1,3

, Isaac Tobin2, Larissa Juschkin

3, Gerry O’Sullivan

1, and Fergal

O'Reilly1

1School of Physics, University College Dublin, Belfield, Dublin 4, Ireland

2School of Physics, Trinity College Dublin, Dublin 2, Ireland

3Department of Physics, RWTH Aachen University, D-52074 Aachen, Germany

The aim of this work is to produce bright EUV photons from laser triggered discharge plasma

formed from liquid Sn coated on rotating-wheel-electrodes. The EUV output was found to

correlate with the localized ablation of the thin film. This was studied by tailoring laser

parameters, mainly the pulse duration and energy density, using two Nd:YAG lasers of

~160ps and ~7ns, each 1064nm, with power density range of ~3-300 GW/cm2.

The picosecond (ps)-laser showed an increase in CE and spectral purity compared to ns-

triggering. The difference, as to the time resolved visible images and ion probe measurements,

is mainly due to the expanding plasma dynamics. The ps-laser produced collimated plasma

with higher axial speed which improved stability during the pinch.

35

DC 12-5

Capillary discharge based XUV sources and applications in imaging

Fahad Nawaz1, J. Limpouch

1, A. Jancarek

1, M. Nevrkla

1, H. Fiedorowicz

2, P. Wachulak

2

1Czech Technical University in Prague, Faculty of Nuclear Sciences & Phy. Engg. Prague,

Czech Republic 2Military University of Technology, Institute of Optoelectronics, Warsaw, Poland


A compact laboratory source based on capillary discharge, working in the “water-window”

range has been optimized for applications in imaging. Nitrogen plasma was exploited as one

of the suitable sources of intensive line radiation in the water window. The focus, in terms of

diagnostics is on the energy of 2.88 nm radiation, corresponding to the 1s2-1s2p quantum

trasnition of helium-like nitrogen. For a realization of a soft x-ray microscope based on

capillary discharge, rotationally symmetric nickel coated ellipsoidal mirror has been

employed for focussing of the 2.88 nm radiation. The spot size at the focus and out of focus,

along with the photon flux at the sample plane for 2.88 nm photons has been measured and

reported. Calculations for a suitable objective (fresnel zone plate) have been carried out,

considering the existing parameters i-e source size, divergence, condenser numerical aperture

and focused spot size etc. Experiments related to similar application with laser-plasma soft x-

ray source at the Military University of Warsaw have been carried out, with some

observations about the fresnel optics. Design of a whole soft x-ray imaging setup (to be

implemented) based on capillary discharge source is outlined.


36

DC 13-1

Compact laser plasma soft X-ray source for contact microscopy

experiments

Mesfin Getachew Ayele, Daniel Adjei, Przemysław Wachulak, Andrzej Bartnik,

Łukasz Węgrzyński, Mirosław Szczurek, Roman Jarocki and Henryk Fiedorowicz


Email:[email protected]

Recent advancements in soft X-ray contact microscopy (SXCM) have improved the ability to

visualize fine cellular structures and their elemental distribution [1-3]. The improvements in

design and performance of soft X-ray sources have increased the resolution up to a few tens

of nanometers to visualize living biological wet cells. Soft X-rays ranging from 1 nm to 10

nm wavelengths can be produced by synchrotron radiation (SR) sources or laser-plasma based

sources. SR sources are able to produce high intensity radiations with reduced exposure time

and can be tuned for elemental mapping. However, limited number and access to SR sources

encouraged development of laboratory scale pulsed laser-plasma based soft X-ray sources,

which produce burst of soft x-rays that can be used to image living wet cells. Laser plasma X-

ray sources that have been used so far in the studies with SXCM technique are based on a

solid target irradiated with nanosecond laser pulses; however, it creates serious problems with

the source operation due to an inevitable target debris production [4]. To avoid this, a source

based on a gas puff target has been proposed that was used in preliminary SXCM

experiments. In this study, a compact laser-plasma soft X-ray source based on a double-

stream gas puff target system has been developed for contact microscopy experiments. The

gas puff target composed of argon encapsulated by helium gas has been irradiated with a

nanosecond Nd:YAG laser pulse operating at 10 Hz repetition rate.Characterisation

measurements of the source, including spectra and soft X-ray yield measurements have been

performed employing a transmission grating spectrograph (TGS) and a silicon PIN

photodiode, respectively. Results of these measurements has demonstrated that strong soft X-

ray yields can be obtained from the argon/helium gas puff target irradiated with high power

laser. Furthermore, optimization of the source has also been carried out in order to maximize

the soft X-ray yield in the ‘water window’ spectral range (280 eV – 540 eV). The laser-

plasma soft X-ray source described in this work provides high intensity and short exposure

time, and will be used in the experiments on soft X-ray contact microscopy.

Acknowledgements: The authors acknowledge financial support from the EU FP7 Erasmus Mundus Joint Doctorate Programme

EXTATIC under framework partnership agreement FPA-2012-0003. With the support from the 7th

Framework

Programme’s Laserlab Eorpoe project (No. 284464).

References

1.Cheng, P. C., R. Feder, D. M. Shinozaki, K. H. Tan, R. W. Eason, A. Michette, and R. J. Rosser. "Soft x-ray

contact microscopy." Nuclear Instruments and Methods in Physics Research Section A: Accelerators,

Spectrometers, Detectors and Associated Equipment 246, no. 1 (1986): 668-674.

2. Michette, A., P., Cheng, R., Easons, R., Feder, F., O'Neill, Y., Owadano, R., Rosser, P., Rumsby and M. J.,

Shaw, “Soft x-ray contact microscopy using laser plasma sources," J phy 19(3), 363 (1986).

3. Batani, D., C.,Botto, M., Moret, M., Milani, G., Lucchini, K., Eidmann, F., Cotelli, C., C., Lora Lamia Donin,

G., Poletti, T., Ford, and Stead, A., "The use of high energy laser-plasma sources in soft X-ray contact

microscopy of living biological samples." Eur Phys J D 21(2), 167-179 (2002).

4. Fiedorowicz, H., A., Bartnik, Z., Patron and Parys, P., "X‐ray emission from laser‐irradiated gas puff

targets," Appl phys lett 62(22), 2778-2780 (1993).


37

DC 13-2

Development of near-edge multi-angle spectroscopic EUV reflectometry

Maksym Tryus1, Larissa Juschkin

1, Serhiy Danylyuk

2, Stefan Herbert

2

1RWTH Aachen University, Chair for Experimental Physics of EUV, Steinbachstr. 15, 52074

Aachen, Germany 2RWTH Aachen University, Chair for Technology of Optical Systems, Steinbachstr. 15, 52074

Aachen, German


Modern nanotechnology is constantly raising demands to quality and purity of thin films and

interlayer interfaces. As thicknesses of employed layers decrease to single nanometers,

traditional characterization tools are no longer able to satisfy throughput, precision or non-

destructibility requirements.

Extreme ultraviolet (EUV) and soft X-ray reflectometry has not only demonstrated the ability

to detect the sub-nm thickness variations but also has shown to be very sensitive to the

chemical composition changes. Extention of spectroscopic reflectometry to multi-angle

measurements allows decoupling of the fitting parameters in the analytical model, making the

method more reliable when characterizing complex layered systems.

The region near elemental absorption edges in reflectivity spectra is of particular analytical

intertest, and complementary to the abovementioned, since it contains Near Edge X-ray

Absorption Fine Structure (NEXAFS). It gives a key to determination of chemical bonds

structure and local-site symmetry of a sample, being irrelative to the presence of long-range

order, thus suitable for studying amorphous and crystalline materials.

Our laboratory setup for multi-angle spectroscopic reflectometry, based on a discharge-

produced plasma EUV source, and first experimental results obtained with Si-based layer

systems, as well as future plans and prospective will be demonstrated and discussed.


38

DC 13-3

Polarization resolved laser produced aluminium plasma emission

1,2

G.A. Wubetu, 1T. Kelly,

1P.V. Kampen,

2H. Fiedorowicz and

1J.T. Costello

1NCPST and School of Physical Science, Dublin City University, Glasnevin, Dublin 9,

Republic of Ireland. 2Institute of Optoelectronic, Military University of Technology, Warsaw, Poland


Laser Induced Breakdown Spectroscopy (LIBS) is an elemental charcaterisation technique

which permits the classification, and potentially the quantification, of atomic elements in a

host material referred to as a matrix [1]. There are significant efforts currently being made

worldwide to increase the main performance parameter of LIBS, namely the limit-of-

detection or LOD. For example single pulse in a background gas and double pulse LIBS is

investigated in the UV-Vis-IR spectral range in many labs. In our laboratory VUV LIBS in

both single pulse [2] and double pulse [3] configurations have been explored. The main figure

of merit underlying LIBS LOD is the signal=to-background ratio or SBR. The main objective

of the current phase of my work is to improve SBR and we will use both variation of laser

parameters and spectral detection to maximise the SBR and hence LOD for this technique.

As a first here is some evidence that Polarization Resolved Laser Induced Breakdown

Spectroscopy (PRLIBS) could be useful in this regard [4]. Hence, we have explored PRLIBS

on an Aluminium (Al) target in vacuo and in air using a Q-switched Nd: YAG nanosecond

laser pulses. PRLIBS has been performed by placing a polarizer in front of the time integrated

spectrometer. We detect polarization anisotropy of optical radiation of the Al plasma plume.

The idea of using PRLIBS is to increase the Signal to Background Ratio (SBR) by improving

the Limit of Detection (LOD). Later we will turn the experiment on its head by varying the

polarisation of the plasma producing laser field.

References:

1. D. W. Hahn and N. Omenettto, Applied Spectroscopy 64 335A-366A (2010)

2. M A Khater, J T Costello and E T Kennedy, Applied Spectroscopy 56 970-983 (2002)

3. X Jiang, P Hayden, J T Costello and E T Kennedy, Spectrochimica Acta Part B: Atomic

Spectroscopy 901 106-113 (2014)

4. L. Yaoming , J. S. Penczak, and R. J. Gordon, Opt. Letts. 35, (2010)


39

DC 13-4

Characterization of TiO2 thin films and novel TiO2/Sc multilayers in the

EUV and Soft X-ray region.

Antonela Comisso1,2

, Piergiorgio Nicolosi 1,2

1 University of Padova, Department of Information Engineering, via Gradenigo 6B, 35131

Padova, Italy. 2 Consiglio Nazionale delle Ricerche—Institute for Photonics and Nanotechnologies

Laboratory for Ultraviolet and X-Ray Optical Research, via Trasea 7, 35131 Padova, Italy


We propose a novel Sc/TiO2 multilayer with high theoretical reflectivity in the soft x-ray

wavelength range, for normal incidence. A theoretical study of the parameters that define the

film stack is performed, observing the effects and impacts of interface imperfections, optical

constants fluctuations, thickness ratio and period changes. Testing performance of the

multilayer for normal incidence near the Sc L2,3 edges (403.6 eV, 398.7 eV). In order to

begin an experimental study of the multilayer, we´ve deposited TiO2 thin films using e-beam

evaporation technique and partially characterized them, studying their surface roughness,

thickness and optical constants.


40

DC 13-5

Photoabsorption in ultrashort duration UV and VUV laser fields

Hu Lu1,2

, Patrick Hayden1, Paul van Kampen

1, Bill Brocklesby

2 and John T. Costello

1

1NCPST and School of Physical Science, Dublin City University, Dublin, Republic of Ireland.

2Optics Research Centre, University of Southampton , Southampton,UK


The overall objective of this project is to investigate the interaction of laser ablated vapours

and plasmas with ultrashort UV and VUV pulses from a variety of laboratory and FEL facility

sources.

At DCU, the dual laser plasma (DLP) technique [1] has been used to investigate VUV and

XUV photoabsorption. In DLP spectroscopic experiments, one laser is used to generate the

back-lighting plasma source of continuum radiation while the other laser is used to produce

the absorbing plasma. By recording photoabsorption spectra at various spatial positions, one

can get a spatio-temporal profile of the plasma. This technique will permit the identification

of resonances that can be subsequently probed with ultrafast VUV and XUV sources. In

particular the formation of the absorbing plasma material, appropriately chosen, can be used

to form a shutter to gate off a fast or ultrafast VUV ot XUV pulse.

In Southampton (Optics Research Centre), the laser ablated atomic vapours and lowly

charged plasma plumes will be probed by few femtosecond coherent XUV high harmonic

generated (HHG) pulses [2] with a view to studying the dynamics of this process.

References

1. J. T. Costello, E. T. Kennedy, J. P. Mosnier, P. K. Carroll and G. O’Sullivan. Physica

Scripta T34, 77 (1991)

2. P. N. Anderson, P. Horak, J. G. Frey and W. S. Brocklesby, Phys. Rev.A 89 013819 (2014)


41

DC 13-6

Coherent diffraction imaging using laboratory light sources

M. Odstrcil, P. Baksh, W. S. Brocklesby

University Southampton, Southampton, UK

Email:[email protected]

Coherent diffractive imaging, also called lenses imaging methods, are now a standard tool for

Xray imaging on synchrotron devices [1,2,3]. The diffractive imaging methods can avoid

limitations of imperfect optics in the Xray region and also limit the dose exposed to the

sample. Therefore, these methods allow to reach higher resolution compared to the standard

lens based methods. Moreover, lensless methods allow to extract full information about the

wavefront behind the sample and hence relative phase and amplitude can be recovered.

Finally, advanced lenseless methods such as ptychography allow to extract information about

the illumination that can be used for beam metrology purposes [3].

In recent years, the coherent diffractive imaging is getting to be used also with the laboratory

sources and longer wavelengths such as EUV and visible light region. Limitation of the

laboratory EUV sources is lower signal, worse coherence properties and generally lower time

stability of the signal. The requirements for lateral and temporal coherence can be slightly

relaxed if the reconstruction is sufficiently overconstrained [4,5,6].

In this work, we will introduce and compare numerical methods that can significantly help to

improve convergence and reconstruction quality. We will introduce the methods using

numerical examples and also real measured data from EUV and IR light experiments. We will

use ptychography method for the reconstruction, although most of the proposed methods can

be used also with other lensless imaging techniques.

References

[1] Rodenburg, J. M. & Faulkner, H. M. L. A phase retrieval algorithm for shifting

illumination. 85, 4795–4797 (2004).

[2] Maiden, A. M. & Rodenburg, J. M. An improved ptychographical phase retrieval

algorithm for diffractive imaging. Ultramicroscopy 109, 1256–62 (2009).

[3] Kewish, C. M. et al. Ptychographic characterization of the wavefield in the focus of

reflective hard X-ray optics. Ultramicroscopy 110, 325–9 (2010).

[4] Enders, B. et al. Ptychography with broad-bandwidth radiation. Appl. Phys. Lett. 104,

171104 (2014).

[5] Abbey, B. et al. Lensless imaging using broadband X-ray sources. Nat. Photonics 5, 420–

424 (2011).

[6] Thibault, P. & Menzel, A. Reconstructing state mixtures from diffraction measurements.

Nature 494, 68–71 (2013).


42

DC 13-7

Laser-produced plasmas of Mo,Ru,Rh and Pd in the 2 to13nm

spectral region

Ragava Lokasani

1,2, Elaine Long

2, Girum Beyene

2, Patrick Hayden

2, Padraig Dunne

2, Jiri

Limpouch1, Akira Endo

3, Fergal O’Reilly

2 &Gerry O’Sullivan

2

1Czech Technical University, Prague, Czech Republic

2UCD School of Physics, University College Dublin, Belfield, Dublin 4, Ireland.

3HiLASE Project, Prague, Czech Republic


The Rayleigh criterion resolution implies that the use of shorter wavelength radiation

improves spatial resolution in photon based imaging and patterning systems. Over the past

decade the development of sources at extreme ultraviolet and even shorter, soft X-ray

wavelength is of a great interest for semiconductor patterning and cellular microscopy where

high resolution is required. In this context we investigated the spectral behaviour of laser

produced plasmas of Mo, Ru, Rh and Pd in the spectral region from 2.5 to 13 nm and their use

as sources for beyond EUV and soft x-ray region.The laser energy range covered by the

experiments was from 623mJ to 5mJ. In the sequence of spectra Mo to Pd, the strongest

emission was observed in the 2-8nm spectral region. Spectral analyses of emission from

different ion stages were identified in successive steps and classification of 3d-4p, 3d-4f and

3p-3d transitions. These transitions in a number of neighbouring of ion stages were identified

by comparison with Cowan code calculations and previous results from spectral studies

particularly on the adjacent elements Mo and Pd.

Acknowledgements


Doctorate Program EXTATIC under framework partnership agreement FPA-2012-0033.


43

DC 13-8

Optics for short pulse X-ray sources

Magdalena Miszczak1, Jeremy G. Frey

2, William S. Brocklesby

1

1Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, UK

2Chemistry, University of Southampton, Southampton SO17 1BJ, UK


The Extreme Ultraviolet (EUV) radiation wavelength range (30–250 eV1) has many

advantages in imaging applications, such as EUV lithography and EUV microscopy. To

achieve high resolution imaging, EUV optics must be able to manipulate and focus the beam.

However, due to the strong absorption of EUV in all materials, experiments must be

conducted in a vacuum. The appropriate selection of chemical reagents and a proper

construction of optical elements in the system, allows the resolution of the image to be

improved. One of the crucial optical components in the optical arrangement is a beam splitter

(BS), which separates the XUV and VIS/IR components of a beam and can be manufactured

as a single layer or multilayer. The BS plays an important role in the High Harmonic

Generation (HHG) process1, where it attenuates the fundamental laser pulse and reflects the

desired harmonic. However, there are only a few beam splitters with good efficiency to

date2,3,4

as it is a challenging task to choose materials and develop structure with high

reflectivity in the EUV spectrum and high attenuation of the fundamental laser pulse. We

explored techniques for the production and characterisation of multilayer structures.

Magnetron sputtering and e-beam evaporator were used to develop optical elements, to

measure surface roughness we applied an optical profilometer.

We are making good progress to producing and testing a new beam splitter consisting of

MoS2 material that has shown from simulations approximatly 76% reflectivity for a

wavelength of 95eV. Introducing this beam splitter into EUV experiments to aid filtering,

could increase the ratio of EUV flux to the attenuation of the fundamental field. The thin film

deposition of MoS2 allows for acceptable surface roughness on the order of tens of

nanometres. The sample will be tested using a reflectometry experiment to investigate

reflectivity in the VIS/near IR spectrum and EUV spectrum. We anticipate our beam splitter

to have reflectivity close to the simulations and to be a starting point to gain experience on

testing more EUV components.

References:

1. D. Atwood, Soft X-rays and extreme ultraviolet radiation, Principles and Applications.

Berkeley: Cambridge University Press, (1999)

2. Y. Nagata, Y. Nabekawa and K. Midorikawa, “Development of high-throughput, high-

damage-threshold beam separator for 13 nm high-order harmonics,” Optics Letter, 31(9),

1316–1318, (2006)

3. E. Takahashi and H. Hasegawa, “High-throughput, high-damage-threshold broadband

beam splitter for high-order harmonics in the extreme-ultraviolet region,” Optics Letter,

29(5), 507–509, (2004)

4. Y. Sanjo, “TiO2/sapphire Beam Splitter for High-order Harmonics,” J. Laser

Micro/Nanoengineering, 7(3), 375–379, (2012)


44

DC 13-9

The slit-less spectrometer: A compact Fourier transform spectrometer

with no moving parts

Stephen J. Davitt, Thomas J. Kelly, John T. Costello

National Centre for Plasma Science & Technology (NCPST),

School of Physical Science Dublin City University (DCU)


Compact spectrometers are becoming increasingly more popular with many research groups

owning at least one of these devices. This is most likely due to: small footprints; impressive

resolution and ease of use of the devices. Companies such as OceanOptics™ and Stellarnet™

offer many different compact spectrometer models to fit specific applications. These

spectrometers are grating based and require an entrance slit typically on the order of one or

two hundred microns in order to achieve the required spectral resolution. However, this

entrance slit limits the spectrometer throughput as it can block out a large proportion of the

available signal.

We propose a compact slit-less spectrometer, based on a design by Andrew Harvey and Miles

Padgett’s for a Fourier transform spectrometer [1,2,3], which uses a Wollaston Prism to create

a spatial interferogram of a light source. The spectral intensity is then calculated by Fourier

transforming the interferogram. This design allows us to achieve the same spectral resolution

as grating based spectrometers but without the use of an entrance slit thereby giving us higher

optical throughput. The use of the Wollaston prism means we can measure the interferogram

without scanning any mirror as is common in conventional Fourier transform spectrometers

such as those based on the Michelson interferometer. This gives us a recording time and/or

signal to noise advantage by reducing the dwell time for any particular spectral component.

This talk is aimed at giving an overview of the progress we have made in the design of such a

spectrometer: from initial investigations to a functioning early alpha stage prototype.

References:

[1] Padgett MJ, Harvey AR, Duncan AJ, Sibbett W. Single-pulse, Fourier-transform

spectrometer having no moving parts. Appl. Optics. 1994 September ; 33(25): 6035-6040

[2] Harvey AR, Begbie M, Padgett MJ. Stationary Fourier transform spectrometer for use as a

teaching tool. Am. J. Phys. 1994 November; 62(11): 1033-1036.

[3] Padgett MJ, Harvey AR. A static Fourier-transform spectrometer based on Wollaston

prisms. Rev. Sci. Instrum. 1995 April; 66(4): 2807-2811.


45

DC 13-10

Numerical modelling of laser-plasma interaction

W Hanks, J. Costello, L A.A. Nikolopoulos

School of Physical Sciences, Dublin City University Dublin, Ireland

and

National Plasma Center for Plasma & Technology, Dublin, Ireland


In this talk I will present our progress on the development of the simulation of the

interactions of plasmas with laser fields. There is much activity and collaboration in the laser

plasma research group in DCU, and so there will be a direct connection between this work on

simulations and the experimental realizations.

Computer simulation of systems is merited as they can be used to: design practical

experiments with the finding of key parameters and conditions to test with physical apparatus;

and to: investigate ahead of practical experiments when the experimental conditions are

difficult to perform.

The equations we are using which describe the laser-plasma interactions are based on the

work of Rambo and Denavit [1]. In their research these equations were solved using finite

difference numerical methods. In our research, finite difference and finite element numerical

methods were considered and studied, and we wish to use a finite element method for our

simulations, and to exploit the most sophisticated algorithmic techniques to date.

In preparation for the modeling of plasmas, we have tested our approach on advection-

diffusion partial differential equations. It is our intention to extend this technique to laser

plasma equations. Our finite element approach utilises the widely successful B-Splines

polynomial basis (in fluid dynamics and most recently, in atomic physics dynamics) [2,3].

References:

[1] PW Rambo, J Denavit. J Comput Phys, 92, 185, (1991) and J Comput Phys, 98, 317,

(1992)

[2] RC Mittal, RK Jain. IJAMC, 4, 115, (2012)

[3] H Bachau et al. Rep Prog Phys, 64, 1815, (2001)


46

DC 14-1

Nanoscale imaging using compact laser plasma SXR sources based on a

double stream gas-puff target and Fresnel optics

Alfio Torrisi1, Przemyslaw Wachulak

1, Henryk Fiedorowicz

1, Ladislav Pina

2

1Institute of Optoelectronics, Military University of Technology, Warsaw, Poland

2Czech Technical University, Prague, Czech Republic


Developments in nanoscience demand tools capable of capturing images with a nanometer

spatial resolution. To extend the diffraction limit associated with the wavelength of radiation,

according to the Rayleigh criterion, one way is to reduce the wavelength, allowing smaller

features to be resolved.

Laser-plasma SXR wavelength is ~100-400x shorter than the visible light and allows to

significantly improve the imaging resolution. The spectral range between the K-absorption

edges of carbon (280 eV) and oxygen (540 eV), which is called “water window”, is attractive

for high-contrast biological imaging.

Laser-plasma gas puff target sources were presented, suitable for SXR microscopy in the

“water window” spectral range. Microscopy with Fresnel zone plates requires a

monochromatic radiation, such as emission from nitrogen plasma SXR source at 2.88 nm

wavelength.

The main motivation for development of a compact, table-top “water-window” sources and

microscopes is to open the possibility to perform experiments without necessity to employ

large “photon facilities” such as synchrotrons or free electron lasers. These compact sources

represent an important alternative to perform some experiments in a university laboratory and

could have a huge impact on the speed of nanotechnology development.

Acknowledgements


Doctorate Program EXTATIC under framework partnership agreement FPA-2012-0033 and

from the 7th Framework Programme's Laserlab Europe project (No. 284464).


47

DC 14-2

Using microstructures for laser-induced X-ray source enhancement from

plasma produced by femtosecond and nanosecond lasers

Ellie Floyd Barte

1,2, Jiri Limpouch

1,Padraig Dunne

2,

1Czech Technical University in Prague, Czech Republic

2UCD School of Physics, University College Dublin, Belfield, Dublin 4, Ireland


Laser-produced plasma X-ray sources are compact and inexpensive and provide intense short

X-ray pulses [1], enhancement of this pulses will be beneficial for future researches and

various applications. One attractive way to increase X-ray pulses generation is to use a

structured surface targets that has a low average density and high local density [2]. By using

also a high-Z material, higher X-ray intensity with a continuous smooth spectrum can also be

achieved [2]. The research aims to achieve a significant increase of X-ray pulses both in the

hard and soft X-ray regions using different targets with defined characteristics.

For the hard X-ray energy region (>1keV), thick layers of low density foam doped by medium

and/or heavy elements will be used as a target for a nanosecond Nd: YAG laser at UCD

Dublin. For the soft X-ray energy region (<1keV), surface layer with microstructures like

nanowires, nanorods, nanoholes array or microspheres will also be used as a targets for the

0.1 TW fs laser at CTU in Prague and 25 TW fs laser at PALS laboratory in Prague.

The results of the experiments will be complemented by numerical modeling of the X-ray

source.

References:

[1] T.Nishikawa, S.Suzuki, Y.Watanabe, O.Zhou, & H.Nakano. (2004). Efficient water-

window X-ray pulse generation from femtosecond-laser-produced plasma by using a

carbon nanotube target. Applied Physics B, 73, 885-890. doi:10.1007/s00340-004-1429-2

[2] T.Nishikawa, H.Nakano, K.Oguri, N.Uesugi, M.Nakao, K.Nishio, & H.Masuda. (2001).

Nanocylinder-array structure greatly increases the soft X-ray intensity generated from

femtosecond-laser-produced plasma. Applied Physics B, 78, 185-188.

doi:10.1007/s003400100625

Acknowledgement:


Doctorate Program EXTATIC under framework partnership agreement FPA-2012-0033.


48

DC 14-3

Coherent diffractive imaging employing a compact discharge plasma EUV

light source

Jan Bußmann

1, Denis Rudolf

1, Lars Lötgering

1, Rui Xu

4, Sascha Brose

3, Serhiy Danylyuk

3,

Jianwei Miao4 and Larissa Juschkin

1,2

1Peter Grünberg Institute 9, JARA-FIT, Research Centre Jülich, 52425 Jülich, Germany

2RWTH Aachen University, Experimental Physics of EUV, JARA-FIT, Steinbachstrasse 15,

52074 Aachen, Germany 3RWTH Aachen University, Chair for Technology of Optical Systems, Steinbachstrasse 15,

52074 Aachen, Germany 4Department of Physics and Astronomy, and California NanoSystems Institute, University of

California, Los Angeles, CA 90095, USA


Diffraction limited microscopy in the EUV and soft X-ray spectral region requires either low

roughness reflective optics or diffractive optics (Fresnel zone plates) structured on the

nanometer scale. The fabrication of such optical elements is difficult and expensive.

Alternatively, a high resolution imaging technique called coherent diffractive imaging (CDI)

offers the possibility to replace the optics completely by image reconstruction algorithms

[1,2].

Experimentally, a sufficiently coherent beam illuminates the test object and the resulting

diffraction pattern is recorded on the detector. Then, the object is reconstructed from its

diffraction pattern by means of phase retrieval techniques [3]. It was demonstrated that the

technique is capable to achieve diffraction-limited lateral resolution [4].

So far, the most experiments were performed at synchrotron and free electron laser facilities.

Only few laboratory based CDI experiments employing either a high harmonic [5] or a soft

X-ray laser source were conducted so far. In our work, we explore the feasibility to perform

CDI with laboratory based high radiance plasma sources developed for EUV lithography.

In this talk, we would like to present our first results of CDI experiments employing a

compact discharge plasma EUV light source [6]. We will address the spatial and temporal

coherence properties of our EUV source which we tuned to fulfill the requirements of the CDI

experiment, show the successful reconstruction of a test object (10 μm pinhole) and the results

of CDI on a test sample. The next steps of the project - ptychography and waveselection by

phase gratings - will be presented in the outlook of the talk.

References

1. J. R. Fienup, “Reconstruction of an object from the modulus of its Fourier transform”, Opt. Lett. 3, 27-29

(1978)

2. C. C. Chen, J. Miao, C. W. Wang and T. K. Lee, “Application of optimization technique to noncrystalline x-

ray diffraction microscopy: Guided hybrid input-output method”, Phys. Rev. B 76, 64113 (2007)

3. S. Marchesini, “Invited Article: A unified evaluation of iterative projection algorithms for phase retrieval”,

Rev. Sci. Instrum. 78, 011301 (2007)

4. H. N. Chapman and K. A. Nugent, “Coherent lensless X-ray imaging”, Nat. Photon. 4, 833 (2010)

5. M.D. Seaberg et al., “Ultrahigh 22 nm resolution coherent diffractive imaging using a desktop 13 nm high

harmonic source”, Opt. Express 19, 22470 (2011)

6. L. Juschkin et al., Proc. of SPIE, Vol. 8849, 88490Y (2013)

7. P. Thibault et al., “High-resolution scanning x-ray diffraction microscopy”, Science 321, 379 (2008)


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BOOK OF ABSTRACTS - Wojskowa Akademia Techniczna...Polarization resolved laser produced aluminium plasma emission 12.45-13.00 A. Comisso Characterization of TiO 2 thin films and novel