1. LCLV and Adaptive Optics
Amar
IUCAA
Advisor: Prof. Ramprakash

2. 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

3. The AO test bench
(correct this schematic)

5. LCLV as a prospective AO
substitute

6. 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.

7. 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.

8. Brewster angle and internal
reflection concept

9. Moire’ and Fourier concept to
convert the phase in a 2D wavefront
into intensity variations.

10. What is needed ??
For a wave front with no
higher order aberrations
Transformation
Intensity

11. What is needed ??
For a wave front with
higher order aberrations
Transformation
Intensity

12. Trying Moire’ and Fourier concepts
Incident LGS
wavefront with
distortions
This is the image plane

13. Trying Moire’ and Fourier concepts
Reference
wavefront
Spatial negative grid
This is the image plane

14. Trying Moire’ and Fourier concepts
Superimpose

15. A Break

16. A Micro Channel Plate

17. The setup
LGS wavefront
Reference
wavefront in
lab
Superimposed
output
Low
intensity High intensity
suitable for
LCLV write sideMCP
Optics

18. How does the flow chart look now

19. 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

20. 1
2 3 4 5
6
7
8
9
10
MCP
Science
11
16
15
13
14
23
24
25
26
27
28
29
30
31
32
17
18
19
20
2122
12

21. (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

22. Thank You