Upload
melina-marsh
View
217
Download
3
Embed Size (px)
Citation preview
17-21 June 2007 ECBO 2007 Munich, Germany
Static depth dependent dispersion compensation in a real-time static delay line
grating-based correlation OCT system
L. Froehly, P. Sandoz, L. Furfaro, M.Ouadour
Institut FEMTO-ST; Département d’Optique P.M. Duffieux Besançon, France
17-21 June 2007 ECBO 2007 Munich, Germany
Dispersion problem in OCT
100m
•Dispersion limits axial resolution
•Dispersion depends on the material thickness
•Dispersion decreases the Signal to Noise ratio
tseS TFenc
j'
12
m1
m13
17-21 June 2007 ECBO 2007 Munich, Germany
Hardware correction
S.L.S.
M1
S1O1
O2
17-21 June 2007 ECBO 2007 Munich, Germany
Hardware correction (rapid scanning delay line)
K. F. Kwong, D. Yankelevich, K. C. Chu, J. P. Heritage, and A. Dienes, Opt. Lett. 18, 558- (1993) ->first demonstration for pulse measurements
Rollins, S. Yazdanfar, M. Kulkarni, R. Ung-Arunyawee, and J. Izatt, Rollins, S. Yazdanfar, M. Kulkarni, R. Ung-Arunyawee, and J. Izatt, Opt. Express 3, 219-229 (1998)Opt. Express 3, 219-229 (1998)
G. J. Tearney, B. E. Bouma, and J. G. Fujimoto, Opt. Lett. 22, 1811-1813 (1997) ->Application of the system to TD-OCT system
17-21 June 2007 ECBO 2007 Munich, Germany
Numerical correction
tIeeI
eItI
dTFjj
jTFd
c
1
•Phase correction in Fourier space•Influence of the phase correction on the image contrast
Quite time consumingQuite time consuming
17-21 June 2007 ECBO 2007 Munich, Germany
Grating-based Tomographic system
y
z
S.L.S.
S1M..: MirrorS: Polarizing beam splitterL1: Spherical lensS.L.S. : White light laser sourceC.B. : Polarizing beam splitterD : CCDR : Diffraction grating 530 gr/mmP : prismO… : Miroscope objectivesE : Sample
I(z)
zt
L1
M2
M3C.B.
D
P
O1
O2
R
4
17-21 June 2007 ECBO 2007 Munich, Germany
M3
M2
R
Principle
I
x↔z
17-21 June 2007 ECBO 2007 Munich, Germany
y
z
S.L.S.
S1
I(z)
zt
L1
M2
M3C.B.
D
P
O1
O2
R
4
Absorption
L. Froehly, M. Ouadour, L. Furfaro, P. Sandoz, T. Gharbi et al, Real-time optical coherence spectrotomography : proof of principle volume 6191 of Biophotonics and New Therapy Frontiers. SPIE, Apr. 2006.
17-21 June 2007 ECBO 2007 Munich, Germany
z
z
Optical Depth dependant dispersion compensation
0 200 400 600 800 10000
1000
2000
3000
4000
5000
6000
7000loi de dispersion du réseau
pixels CCD
z
17-21 June 2007 ECBO 2007 Munich, Germany
Optical Depth dependant dispersion compensation : principle
17-21 June 2007 ECBO 2007 Munich, Germany
Optical Depth dependant dispersion compensation : principle
17-21 June 2007 ECBO 2007 Munich, Germany
Optical Depth dependant dispersion compensation : principle
17-21 June 2007 ECBO 2007 Munich, Germany
0 200 400 600 800 10000
1000
2000
3000
4000
5000
6000
7000loi de dispersion du réseau
pixels CCD
Optical Depth dependant dispersion compensation : validation
17-21 June 2007 ECBO 2007 Munich, Germany
0 200 400 600 800 10000
0.5
1
1.5
2
2.5x 10
4 dispersion 2 lames
pixels CCD 0 200 400 600 800 10000
0.5
1
1.5
2
2.5
3
3.5x 10
4 dispersion 1 lame
pixels CCD
Optical Depth dependant dispersion compensation : validation
17-21 June 2007 ECBO 2007 Munich, Germany
0 200 400 600 800 10000
1000
2000
3000
4000
5000
6000
7000loi de dispersion du réseau
pixels CCD
0 200 400 600 800 10000
0.5
1
1.5
2
2.5
3
3.5x 10
4 dispersion 1 lame
pixels CCD
0 200 400 600 800 10000
0.5
1
1.5
2
2.5x 10
4 dispersion 2 lames
pixels CCD
Optical Depth dependant dispersion compensation : validation
17-21 June 2007 ECBO 2007 Munich, Germany
0 200 400 600 800 10000
1000
2000
3000
4000
5000
6000
7000loi de dispersion du réseau
pixels CCD
0 200 400 600 800 10000
1000
2000
3000
4000
5000
6000
7000
pixels CCD
0 200 400 600 800 10000
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
pixels CCD
Optical Depth dependant dispersion compensation : validation
17-21 June 2007 ECBO 2007 Munich, Germany
Future directions: lens effect on dispersion
17-21 June 2007 ECBO 2007 Munich, Germany
Future directions : lens effect on dispersion
17-21 June 2007 ECBO 2007 Munich, Germany
Future directions : catadioptrics systems
y
z
S.L.S.
S1
M2
M3C.B.
P
O1
O2
R
4
D
17-21 June 2007 ECBO 2007 Munich, Germany
Aknowldegments
•French ANR who finances this project•Leukos innovative systems who provide us with microchip-based supercontinuums