LCLV front end optics

LCLV and Adaptive Optics

Amar IUCAA

Advisor: Prof. Ramprakash

AO Test Bench Flowchart

Sky simulator Atmospheric distortion simulator

Telescope simulator

Laser guide star

Tip-tilt open/close loop

DM open/close loop, higher order correction

Science instrument

The AO test bench (correct this schematic)

LCLV as a prospective AO substitute

Stating the problem for higher order corrections

•  The writing light has intensity variations and this intensity variations is transformed into phase variations in the reading side.

•  Need to convert the phase changes to intensity changes effectively.

Who are the proposed candidates

•  Brewster angle concept. •  Internal reflection concept. •  Moire’ and Fourier transformation concept.

Whom do I prefer

•  Moire’ and Fourier transformation concept.

Brewster angle and internal reflection concept

Moire’ and Fourier concept to convert the phase in a 2D wavefront

into intensity variations.

What is needed ??

For a wave front with no higher order aberrations

Transformation Intensity

What is needed ??

For a wave front with higher order aberrations

Transformation Intensity

Trying Moire’ and Fourier concepts

Incident LGS wavefront with distortions

This is the image plane

Trying Moire’ and Fourier concepts

Reference wavefront

Spatial negative grid

This is the image plane

Trying Moire’ and Fourier concepts

Superimpose

A Break

A Micro Channel Plate

The setup LGS wavefront

Reference wavefront in lab

Superimposed output

Low intensity High intensity

suitable for LCLV write side

MC

P

Optics

How does the flow chart look now

AO Test Bench Flowchart

Sky simulator Atmospheric distortion simulator

Telescope simulator

Laser guide star

Tip-tilt open/close loop

DM open/close loop, higher order correction

Science instrument

Reference laser wavefront

1 2 3 4 5

6

78

9

10

MC

P

Science 11

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26

27 28

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(1)  Sky Simulator Screen (2)  Optics (3)  Wedge (4)  Transparency sheet or a hot plate (5)  Optics (6)  Optics (7)  LGS mirror (8)  Cassegrain secondary mirror (9)  Cassegrain primary mirror (10)  Folding mirror (11)  Reference laser (12)  Optics for reference laser (13)  Narrow band laser frequency filter (14)  Optics (15)  Spatial grid (16)  Spatial negative grid (17)  Superimposing optics (18)  Wavefront with local phase distortions shown up as

intensity distortions. (19)  Microchannel Plate for light amplification suitable for

LCLV system. (20)  Wavefront with optimum light amplification for

LCLV system (21)  Optics (22)  LCLV system (23)  Folding mirror (24)  Tip-tilt mirror (25)  Optics (26)  Off axis optics to shift the target light (27)  Fold mirror (28)  Tip-Tilt sensor

(29) Electronics for algorithm (30) Optics (31) Optics (33) Fold mirror

Thank You