Achromatization of the Self-Coherent Camera (SCC)

Transcription

Achromatization of the Self-Coherent Camera (SCC)
Jacques-Robert Delorme
"
THD Team: R.Galicher, P.Baudoz & G.Rousset
Collaborators : J.Mazoyer, M.N’Diaye & K.Dolhen
"
JR Delorme / Workshop ONERA
1
Tuesday 20 January 2015
Principle of coronagraph
Lyot stop
Image
Space telescope"
or"
Ground telescope "
with AO
DM"
(pupil plane)
As
Phase mask
Lyot stop
2
As = complex
amplitude of the
speckle field
Principle of the SCC
Modified Lyot stop
SCC Image
ξ0
AR
DM"
(pupil plane)
As
Phase mask
Lyot stop
3
The equation of the SCC image
Modified Lyot stop
ξ0
SCC Image
!
2
2
I( x, λ ) = AS + AR
! ! %
" 2π i x.
ξ0
+AS* AR exp $ −
'
λ
#
&
! ! %
"
2π i x. ξ 0
*
+AS A R exp $ +
'
λ
#
&
!
I( x, λ ) = AS
+ AR
2
2
!
!
! 2iπ x. ξ $
0
+2 Re ( AS AR ) cos #
&
λ
"
%
4
The equation of the SCC image
SCC Image
reference hole
Modified Lyot stop
ξ0
classical Lyot
!
2
2
I( x, λ ) = AS + AR
! ! %
" 2π i x.
ξ0
+AS* AR exp $ −
'
λ
#
&
! ! %
"
2π i x. ξ 0
*
+AS A R exp $ +
'
λ
#
&
!
I( x, λ ) = AS
+ AR
Spatial modulation
5
2
2
Speckle intensity
Reference intensity
!
!
! 2iπ x. ξ $
0
+2 Re ( AS AR ) cos #
&
λ
"
%
Fourier transform of the image
Fourier plane
ξ0
λ
!
FT (I ) = FT AS + AR ⊗ δ (u )
!
"
%
!
ξ
*
+FT ( AS AR ) ⊗ δ $ u + 0 '
λ&
#
!
"
%
!
ξ
*
+FT ( AS AR ) ⊗ δ $ u − 0 '
λ&
#
(
6
2
2
)
Estimation of the speckle field
Fourier plane
FT-1
A sA r*
AsAr* = Estimation of the
complex amplitude
of the speckle field
See : J.Mazoyer & al., A&A, 2014
7
How to build the control matrix?
1
To do
Est_1
2
To do
Est_2
N
To do
Est_N
8
Interaction
Matrix
Est_N
A sA r*
Est_1
Est_2
Est_3
Est_4
SCC Image
DM Shape
How to build the control matrix?
1
To do
Est_1
2
To do
Est_2
N
To do
Est_N
9
Generalized Inverse
Interaction
Matrix
Est_N
A sA r*
Est_1
Est_2
Est_3
Est_4
SCC Image
DM Shape
Correction in closed loop
DM
Phase mask
Lyot stop
Control_Matrix . (AsAr*)
10
One!
single
Image
A sA r*
Numerical simulations: mono-λ light
Contrast curve
32 λ0/D
Contrast (RMS)
13.5 λ0/D
DM cutoff
Separation in λ0/D
32*32 actuators / phase: 10nm (RMS) / amplitude: 10% (RMS)
PSD : f-2
/ PSD : f-1
λ0 = 635 nm
11
Numerical simulations: poly-λ light
Polychromatic Correction
Contrast curve
Contrast (RMS)
∆λ = 40nm
Mono-λ
∆λ = 40nm R = λ0/∆λ= 16
λ0 = 635 nm
Separation in λ0/D
12
Cumulative function
Cumulative function
Mono-λ
∆λ = 40nm
Contrast
13
Cumulative function
Cumulative function
90 %
50 %
Contrast
14
Polychromatic light = Blurred fringes
After correction
Before correction
Numerical simulation : λ0 = 635 nm / Δλ = 40 nm / R = 16
15
After correction
Before correction
Fringes !
=!
Correction
16
After correction
Before correction
Fringes !
=!
Correction
Blurred Fringes !
=!
Low Correction
17
1 reference SCC
Image
Modified Lyot stop
Image
ξ0
Fringe period = λ/ξ0
18
Multi-Reference SCC : MRSCC
Image
MRSCC
modified Lyot stop
19
Estimation by MRSCC
Fourier plane
Estimation # 1
&
Estimation # 2
Estimation
correlation between
ref 1 & ref 2
20
Correction in closed loop with MRSCC
DM
Phase mask
Lyot stop
Control_Matrix . (AsAr*)
21
One!
single
Image
Estimation
Performance of the MRSCC
poly-λ + MRSCC (2 ref)
22
mono-λ
SCC
poly-λ
SCC
poly-λ
MRSCC (2 ref)
23
Cumulative function
Contrast (RMS)
Cumulative function
Contrast curve
poly-λ!
SCC
poly-λ!
MRSCC
Contrast
Separation in λ0/D
Mono-λ
24
THD-Bench
Talk R.Galicher this afternoon
25
THD-Bench
Camera
Modified Lyot Stop
Phase Mask
Kilo DM BMC
Talk R.Galicher this afternoon
26
Laboratory results at λ0 = 638 nm
10.5 λ0/D
Monochromatic Correction
23 λ0/D
Contrast (RMS)
3 10−8 "
Phase Mask = DZPM
Provided by collaborators (LAM)
Separation in λ0/D
27*27 actuators in pupil
"
btw 6 & 12λ0/D"
27
Mono-λ SCC correction!
Image recorded at Δλ = 80 nm
Contrast curve
Contrast (RMS)
3 10−8 "
btw 6 & 12λ0/D"
Separation in λ0/D
28
Mono-λ SCC correction!
Poly-λ SCC correction!
Image recorded at Δλ = 80 nm Image recorded at Δλ = 80 nm
29
The Multi-Reference SCC
Modified
Lyot stop of the THD-bench
SCC Image
30
The Multi-Reference SCC
Mono-λ SCC correction
Poly-λ MRSCC correction
Image recorded at Δλ = 80 nm Image recorded at Δλ = 80 nm
31
Multi-Reference SCC Correction
Cumulative function
Contrast (RMS)
Cumulative function
Contrast curve
poly-λ!
SCC
poly-λ!
MRSCC
DM cutoff
Separation in λ0/D
Contrast
32
Multi-ref SCC (MRSCC)
Conclusion
Lab. results
Perspectives
Multi-reference SCC:"
Monochromatic SCC "
•
•
" Contrast < 3 10−8 btw 6 & 12λ0/D"
‣ optimization of the estimation"
"
•
Multi-reference SCC (3 references)"
•
"
•
"
Association with an IFS:"
}
‣ Sphere: R = 30-50"
‣ GPI: R = 35-78 "
" Monochromatic : "
Same as 1 reference SCC"
MRSCC"
ready to use
"
" Polychromatic (Δλ = 80nm): "
THD-Bench:"
close to the mono-λ correction"
•
"
Enlarge the bandwidth:"
33
See : R.Galicher this afternoon"
Lab. Performance
λ0 = 638 nm
Δλ = 80 nm
R=8
"
Phase Mask: DZPM
34

Achromatization of the Self-Coherent Camera (SCC)

Transcription

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