Filippo M. Zerbi on behalf of JRA-6 Team OPTICON Mid Term review JRA-6 Mid-Term Report Filippo Maria Zerbi on behalf of

Filippo M. Zerbi on behalf of JRA-6 Team OPTICON Mid Term review

JRA-6 Mid-Term Report

Filippo Maria Zerbi

on behalf of JRA-6 Team

Filippo M. Zerbi on behalf of JRA-6 Team OPTICON Mid Term reviewFilippo M. Zerbi on behalf of JRA-6 Team OPTICON Mid Term review

JRA 6 in a Nutshell

JRA-6 is entitled “Volume Phase Holographic Gratings”

The following Contractors contribute to JRA-6:• ESO European Southern Observatory (INT)• IAC Instituto de Astrofisica de Canarias (E)• INAF Istituto Nazionale di Astrofisica (I)

• Osservatorio Astronomico di Brera (Coordinator)• Politecnico di Milano (I)

• Diapartimento di Ingegneria Chimica• Universitè de Liege (B)

• CSL Centre Spatial de Liege (ATHOL)

Purpose of the JRA-6 is to enhance the applicability of VPHGs in Astronomical Instrumentation


VPHGs ?


VPHGs ?

a “slice” of photosensitive material with n modulated by an interferometric pattern of fringes grooved in by holography.

The PS-material is embedded in glass components, active or passive following the optical design, that can be AR-coated

The orientation of the fringes determinesthe reflection or transmission behavior.


Regular pattern of varying refractive media with scale-length of the same order as .

sensen 21 nnmd

Multiple reflection anddiffraction in a multi-layerconfiguration

Bndm

22

sen2

VPHGs ?


• VPHGs Efficiency Predicted via RCW-Theory - Commercial or custom codes (U-Mich – INAF-Brera).•“Back of an envelope” estimates via the Kogelnick (1962) approximation

B

nLsen

2

2

cos

There is a pair B, 2B for which maximum coherence/efficiency is reached

For a given *2B minimum coherence/efficiency is reached for = B ± . This defines the BLAZE function B(, *2B)

If we scan the Bragg angle (e.g. rotating the VPHG) the maximum coherence/efficiency is reached at different values. This defines the SUPERBLAZE function SB(B, 2B).

Crucial Quantities

VPHGs ?


Blaze and superblaze are at some extent “tunable” in width and height to ones needs fiddling with n and L

VPHGs ?


Photosensitive Material ? Baseline: Dichromated Gelatin

PROs•Very High Transmission in VIS-NIR•Suited for (n L) needed for gratings

CONs•Dirty Wet Chem Post-processing•Higroscopic•No redder than K-band

THE limit to VPHGs performances

VPHGs ?


Relevance of VPHGs in Astronomy


VPHGs in Astronomy

Efficiency

Gain


Easy Handling and Maintenance

OPTICON- JRA6

VPHGs in Astronomy


As Grism in low resolution spec.

Implemented:•AFOSC@ ASIAGO 1.8 mt•d.o.lo.re.s @ TNG 3.6 mt•FORS@VLT 8.2 mt•VIMOS@VLT 8.2 mt

Planned:•EFOSC@ESO 3.6 mt•EMIR@GTC 10mt•MUSE@VLT 8.2 mt•XXX@EELT 42mt

As Cross Disperser in HR spec.

Planned:•UVES@VLT 8.2 mt •Espresso@VLT 8.2 mt•CODEX@EELT 42mt

As Core element in HR spec.

Planned:•SONG Project (0.8 mt)•REM Telescope (0.6 mt)•………..

VPHGs in Astronomy


Status “ANTE-OPTICON”


•First fully functional prototype used at AAO (K.Taylor, G.Robertson) – 1997(8)

•Pioneering USA work under NSF grant at NOAO (Sam Barden) collaboration with Kaiser Optical (Jim Arns) -1997-2000 (single world producer at the time).

•Richard Rallison (Utah) steps into the market with cheap (but not always science-grade) devices – 1999

•Chris Clemens hosts at UNC two “thinkshops” (1999 and 2000) to join efforts of the astronomical community toward the use of VPHGs

Status “ANTE”


Dimensions. First problem to solve. •Kaiser Optical and Rallison max size 10 cm. •Pupils of exisiting instruments 20 cm. ELTs pupils >40 cm

Players. Second problem to solve. •As single HQ player on the market implies vendor dictates the rules •Astronomy needs “outsourcer reactive to stimuli”, i.e. competition

USA. Third “problem” to solve. •The EU-USA competition (or “coopetition”) in Astronomy is high.•USA technology is “not always” available to other countries

Status “ANTE”


Financial Contribution in “stocks” of 12.5 k€ entitling to receive 1 VPHG at wish

Co-leaders

Goal:Creation of a pole (spin-off) to produce large size Astronomical VPGHs in Europe

Status “ANTE”


ATHOL

Partner of JRA-6 through ULG

Status “ANTE”


JRA-6 Goals and Timeline


JRA-6 Goals

Selected Areas of research

• IR VPHGs: Enable VPHGs technology in the NIR (1-2.5 microns) regime in cryogenic instruments.

• UV VPHGs: Enable VPHGs technology in the UV (300-450 nm) regime with particular attention to cross dispersers.

• DCG Replacement: Look for a replacement of the DCG as photosensitive element.

• Non-traditional Configurations: Enhance the applicability of “traditional” VPHGs.


JRA-6 programme (OPTICON Contract Annex 1) is aimed to:

• WP2 - Fabrication of fully functional VPHGs working at cryogenic (77 k) temperature and optimized for IR (1-2.5 µm) wavelengths

• WP3 - Improved perfromances VPHGs at visible wavelengths withattention to cross-dispersion, tuneability of the resolution, FPA filling.

• WP4 - Fabrication of the first laboratory-level re-writeable VPHG based on photochromic polymers.

Added at Kick-off (as re-destribution of WP workload):

•WP5 – Fabrication of fully functional VPHGs working at UV (300-450 nm) wavelengths with special care to cross-dispersion.

JRA-6 Goals


JRA-6 general (for each WP) milestones scheme:

•Definition of a prototype characteristics •Fabrication of the prototoype •Analysis and characterization of the prototype •Definition of the final deliverable characteristics •Production of the final deliverable •Analysis and characterization of the final deliverable•Final product dossier editing.

JRA-6 detailed milestones scheme (Annex I of OPTICON Contract)

•6 milestones (M1-M6) specializing the above scheme to each WP

JRA-6 Goals


6m 12m 18m 24m 30m 36m 42m 48m 54m 60m

WP1 D1

WP2 M1 M2 M3 M4 M5 M6 D1

WP3 M1 M2 M3 M4 M5 M6 D1

WP4 M1 M2 M3 M4 M5 M6 D1

WP5 M1 M2 M3 M4 M5 M6 D1

Prototyping Phase Final deliverable Phase

JRA-6 Goals


WP-2 IR VPHGs


Prototype IR-J1 Prototype IR-H1 Prototype IR-K1

Substrate material IR-Fused silica. IR-Fused silica. IR-Fused silica.

Substrate dimensions 100x100x10 mm 100x100x10 mm 100x100x10 mm

Clear aperture Ø35 mm Ø35 mm Ø35 mm

Line density 1156.78 867.52 646.68

Operating range 1100 – 1400 nm 1500 – 1800 nm 2000 – 2400 nm

Efficiency>40% at 1100 nm>90% at 1250 nm>40% at 1400 nm

>50% at 1500 nm>90% at 1650 nm>40% at 1800 nm

>50% at 2000 nm>90% at 2200 nm >40% at 2400 nm

AR Coatings none none none

Wavefront error /2 /2 /2

WP-2

Prototype Definition


Prototype Manufacturing

WP-2


Specific Setup built

WP-2


1000 1100 1200 1300 1400 15000

10

20

30

40

50

60

70

80

90

100 RCWA

41

40

34 3536

38

39

28

29

30

3732

33

31

27

Opticon IR-J1a

Tra

nsm

itta

nce

[A

.U.]

Wavelength [nm]

1200 1300 1400 1500 1600 17000

10

20

30

40

50

60

70

80

90

100 RCWA

28

29

30

3432

33

31

27

26

Opticon IR-H1a

Tra

nsm

itta

nce

[A

.U.]

Wavelength [nm]

Efficiency

WP-2


500 1000 1500 2000 25000.0

0.2

0.4

0.6

0.8

1.0

Dif

frac

tio

n e

ffic

ien

cy

Wavelength [nm]

Higher Order Contamination

WP-2


0 2 4 6 80

2

4

6

8

Opticon IR-H1a 2->3

1.0

0.5

2.0

2.5

1.5

PV = 3.0 RMS = 0.564 PWR = 1.546

0 2 4 6 80

2

4

6

8

Opticon IR-K1 10->13

1.0

0.5

2.0

1.5

PV = 2.2 RMS = 0.53 PWR = 1.87

0 2 4 6 80

2

4

6

8

3.0

Opticon IR-J1a 9->8

1.00.5

2.0

2.5

1.5

PV = 3.38 RMS = 0.59 PWR = 2.00

WP-2


small grating: 95% efficient at 633 nm, Bragg 25°.WP-2


Ongoing Activity

• Full Cryo-analysis of specific IR prototypes (delayed).• Definition of Science Grade devices characteristics.• Procurement of the substrates for the Science Grade devices.

Planned Activity

• Manufacturing of the Science Grade Devices• Characterization of the Science Grade Devices

WP-2


WP3 Non Traditional Configurations


A) VPHG-based Tunable narow-band FIlter

B) Multiple trace VPHG HR spectrograph

WP-3


Tunable Filters

WP-3


HR Spec.

WP-3


Double Pass UV Cross Disperser

WP-3 & WP-5

ext

VPHG

In

Dif

Reflect

Trans

ext

45°

'ext

Mirror

'ext


Ongoing Activity

• Construction of the Mechanical parts of HR spec. (delayed)• Definition of specific VPHGs for the Tunable Filter• Procurement of the substrates for the VPHGs

Planned Activity

• Integrating and Testing the HR spectrograph.• Integrating and Testing the Tunable Filter .

WP-3


WP-4 Photochromic Polymers


SS CH3

CH3

F

F

F F

F

F

A

[B]

A

[B]SS CH3

CH3

F

F

F F

F

F

A

[B]

A

[B]

h

h

Write with light - Wipe with Light - Re-write with light

Linear - Transparency

Non linear – Polarizability (n)

WP-4


S

Br2, AcOH

S

Br

Br

BuLi, B(OMe)3

S

Br

2(HO)B

Br

R

S

Br

R

S

Br

R

F

FF F

F

F

F F

BuLi

SR

F

FF F

F

F

SR

HCl

1: R = H2: R = OMe3: R = CN

SOHC CH3 SS

F FF

F

F

F

OHC CHOF FFF

FF

FF

S CH3

CH3O

CH3O

Br

SOHC CH3

BrBuLi

SS

F FF

F

F

F

N N NNR'

R'' R''

R'4: R', R'' = CH3

5: R'= Ph; R''= H

Zoology derived for OTPICON applications

“LEGO Chemistry”

WP-4


WP-4


Ongoing Activity

• Production of Better Quality Photochromic Films • Definition of the Final deliverable Characteristics

Planned Activity

• Production of a Higher Performances Phot-VPHGs• Characterisation of its perfromances.

WP-4


WP-5 UV VPHGs


UV-1 UV-3 Substrate and cover plate

2x Fused Silica 100 x 100 x 8 mm Surfaces 150 nm rms

Line density 1006 l/mm 1000 l/mm ? Optical arrangement Single-pass 1st order Double-pass

Zero order/1st order Operating Range 300 - 390 nm

300 – 390 nm ?

Efficiency goal > 70% @ 300 nm > 90% @ 345 nm > 70% @ 390 nm

> 50% @ 300 nm > 85% @ 345 nm > 50% @ 390 nm

Wavefront Not Specified (surfaces would result in ~ 75 nm rms)

Coatings None

Prototype Definition

WP-5


WP-5


Efficiency

UV-3 / 1st order diffraction efficiency

0

10

20

30

40

50

60

70

80

90

100

300 320 340 360 380 400 420 440 460 480 500

Wavelength (nm)

Effi

cien

cy (

%)

Reflection grating

α ext=10°

α ext=12°

α ext=14°

WP-5


47

0 2 4 6 80

2

4

6

8

2.5

2

Opticon UV1 6-7 power removed

1.5

1

2

1.5

0.5

PWRzygo

= 4.680 PV = 2.742 RMS = 0.503

0 2 4 6 80

2

4

6

8

Opticon UV1 6-7

5

4

2

1

3

PV = 5.747 RMS= 1.187

(633 nm)0123456

Transmitted Wavefront

WP-5


Double Pass UV Cross Disperser

WP-3 & WP-5

ext

VPHG

In

Dif

Reflect

Trans

ext

45°

'ext

Mirror

'ext


UV-3 / 0 order efficiency

0

10

20

30

40

50

60

70

80

90

100

300 350 400 450 500 550 600

Wavelength (nm)

Effi

cien

cy (

%)

α' ext =33° (surfaces)

α' ext =33° (DCG)

α' ext =33° (total)

UV-3 / double pass diffraction efficiency

0

10

20

30

40

50

60

70

80

90

100

300 320 340 360 380 400 420 440 460 480 500

Wavelength (nm)

Effi

cien

cy (

%)

Reflection grating

Double pass, 10° (th)



Double pass, 12° (meas)

GoalEfficiency

New set of prototypes manufactured

WP-5


Ongoing Activity

• Characterization of the new set of prototypes (delayed)• Definition of Science Grade devices characteristics.• Procurement of the substrates for the Science Grade devices.• Procurement of the prism for Cross-disperser-configuration

Planned Activity

• Manufacturing of the Science Grade Devices• Characterization of the Science Grade Devices

WP-5


Conclusions

• Work is progressing generally in schedule. – The viability of the technology has been demonstrated– The way toward science grade devices has started

• There are some minor (not impacting the final deliverable) delays– Due to “problems”, e.g. manpower, cash-flow, delays in parts delivery, etc.– Due to intermediate results, e.g. decision to modify a parameter or build a new

prototype, etc.

• My personal overall judgment of JRA6 activity is extremely positive.

Documents

Filippo M. Zerbi on behalf of JRA-6 Team OPTICON Mid Term review JRA-6 Mid-Term Report Filippo Maria Zerbi on behalf of