The European RTNThe European RTN

(Research Training Network)(Research Training Network)

on AO for on AO for ELTsELTs

M. Le Louarn

NETWORK PARTNERS

Funding:

Network activitiesAO for ELT

ELT⇔ AO design &Strategy

ELT⇔ AO design &Strategy

Micro-mirrorR&D

Micro-mirrorR&D

New wavefront sensors

New wavefront sensors

Key areas addressed by the RTNKey areas addressed by the RTN

3D-Wavefrontsensing:

Tomography

Multi-conjugateAO

AO strategy for ELT & science impact

Cophasing oflarge segmented

mirrors

Large Deformable mirror R&D

WP 2

WP 4WP 1

WP 3

WP 5

Top level requirementsTop level requirementsELT design and AO constrainsELT design and AO constrains

Finite outer scale effectFinite outer scale effectDeformable mirror requirementsDeformable mirror requirementsKnowledge of the atmosphereKnowledge of the atmosphere

Preliminary road-map for AO onPreliminary road-map for AO onELTsELTs

OWLOWL

VLTVLT

Analytic AO simulation : L0 effectAnalytic AO simulation : L0 effect

50%

80%

Effect of a finite outer scale of turbulence on the turbulent modesto be corrected: 100 first modes are much attenuated for OWL

R. Conan et al. 2002

Adaptive Optics TomographyAdaptive Optics TomographyWavefront sensing and 3 D WFSWavefront sensing and 3 D WFS

Multi-Conjugate Adaptive Optics (MCAO)Multi-Conjugate Adaptive Optics (MCAO)Star oriented MCAOStar oriented MCAO

Layer oriented MCAOLayer oriented MCAOMulti-Multi-FOV FOV Layer Oriented MCAOLayer Oriented MCAO

LGS MCAOLGS MCAO

Scale: 0.10 ESO 05-Mar-02

250.00 MM

1st deformable mirror

2nd deformable mirror

derotator

collimator

wavefront sensor objective

dichroic

to IR imaging

camera

Nasmythfocus

MAD optical designMAD optical design

derotator+/- 1’ FoV

derotator+/- 1’ FoV

CollimatorF=900 mm

CollimatorF=900 mm

F/15 Nasmythfocus

F/15 Nasmythfocus

MACAO-VLTIDM 100 mm9 Km conj.

MACAO-VLTIDM 100 mm9 Km conj.

MACAO-SINFONIDM 60 mm0 Km conj.

MACAO-SINFONIDM 60 mm0 Km conj.

DichroicIR/Vis

DichroicIR/Vis

To IR Camera1-2.5µµµµm

2kx2k, 1' FOV

WFSRe-imaging

objective

WFSRe-imaging

objective

TelecentricF/20 focus

TelecentricF/20 focus

To WFS 2’0.45-0.95µµµµm

Thorough lab testing w/ turbulence generator to test control algorithms + understand MCAO. Compare Star and Layer oriented approaches

MAD Star Oriented expected performanceMAD Star Oriented expected performance

! Numerical simulations

! 7 layers atmosphere, seeing 0.65” at zenith and 30° from zenith

! MAD system, 3 Natural Guide Stars! Performance in K band (2.2 µm): Peak Strehl / Strehl variation

2’1’ 1’ FoV

2’ FoV

FoV Zenith 30°

1’ 0.45/0.13 0.42/0.21

2’ 0.31/0.13 0.28/0.21

Layer Oriented expected performanceLayer Oriented expected performance

! Numerical simulations

! 7 layers atmosphere, seeing 0.67”, no outer scale, at 30° (no zenith)

! MAD system, 3-8 NGSs integrated magnitude mv<14! Performance in K band (2.2 µm): Peak Strehl / Strehl rms

3 NGSs 1’ FoV

8 NGSs 2’ FoV

# NGS 1’ FoV 2’ FoV

3 NGS 0.43/0.05 0.31/0.06

# NGS-2’ FoV mint:10 12 14

6 NGS 0.43/0.09 0.40/0.05 0.29/0.05

8 NGS 0.44/0.06 0.41/0.06 0.28/0.06

High Density deformable mirrorsHigh Density deformable mirrorsLarge deformable mirrorsLarge deformable mirrorsHigh density micro-mirrorsHigh density micro-mirrors

Adaptive "Adaptive "secondariessecondaries" (" (ArcetriArcetri))

M2 - Flat, 33.4-m,segmented

M1 - Spherical, 100-m, f/1.42, segmented

M3 - Aspheric, 8.2-m, thin active meniscus

M4 - Aspheric, 8.1-m, thin active meniscus

M6 - Flat, 2.5-m, Exit pupil, field stabilization

M5 - Aspheric, 4.0-m, Focusing

Adaptive mirrors (conjugated to 0, 8 km)7000-20000 actuators

• A cost-effective design optimised for MCAOand for low sensitivity to error sources

• Prototype adapt. second. @ VLT ?

MOEMS (obs. Marseille)

"MDM conception, realization and characterization, since 2001

# Collaboration with LAAS (Toulouse-France)

# Manpower: LAM (2 p. + PhD student);

LAAS (2 p. + Post-Doc (AO-ELT, starting this

fall))

# Device characterization

• Characterization bench under development

• Tests on prototypes developed by LAAS

"Projects

# VLT 2nd generation

• PF (LAOG, LAM, Obs. Paris-Meudon, Obs. Nice, …)

• FALCON (Obs. Paris-Meudon, LAM)

# OWL

• AO-ELT network

Large segmented mirrorsLarge segmented mirrorsEffect of segmentation Effect of segmentation cophasingcophasing

Point Spread Function qualityPoint Spread Function qualityWavefront sensing for Wavefront sensing for cophasingcophasingMach Mach ZehnderZehnder, curvature, Shack, curvature, Shack

Hartmann, Pyramid…..Hartmann, Pyramid…..

SegmentationSegmentationerrorserrors

Gaps

Piston error

Edge misfigure

Tip-tilt error

Diffractionpeaks

PSF

Yaitskova et al. 2002

All effects: Strehl ratio and relative intensity of the firstorder diffraction peaks

____0.96exp(-rms2)λ/30 (WF)3300

rmssegments, N

Piston

2.5_10-50.013rms40.961-rms2+

rms4(2.34+2/N)/4λ/30 (WF)3300

rmssegments, N

Tip-tilt

7_10-5 – 3_10-4< 0.5( η/d )20.94 –

0.97> 1-3.3_(2η/d)+ 4.5_(2η/d)2

0.25µm (WF)20 -10mm

depth, εwidth, η

Turnededges

4_10-50.7(δ/d) 20.98(1-δ/d)412mm1.5m

gap size, δsegment size d

Gap

ValueExpressionValueExpression

Relative intensityof A1 peaks

Strehl ratioTypicalvalue

Criticalparameters

Effect

Yaitskova et al. 2002