1. Quantum Imaging: Q-OCT Department of Electrical & Computer Engineering
Bahaa Saleh
Alexander Sergienko
Malvin Teich
Quantum Imaging Lab
Department of Electrical & Computer Engineering
&
Photonics Center
MURI 6/9/05

2. Outline
Quantum Imaging
Two-Photon Imaging
Quantum OCT
MURI 6/9/05

3. Outline
Quantum Imaging
Two-Photon Imaging
Quantum OCT
MURI 6/9/05

4. Optical Imaging
= Estimation of the spatial distribution (2D, 3D, 4D) of a
physical object by use of optical measurement (direct or
interferometric)
Source
Reflectance
R(x,y)
Conventional Imaging
Metrology
Detector or
R(x,y,)
Spectral or
Hyperspectral Imaging
or Jones matrix
J(x,y)
Polarization-sensitive
Imaging (Ellipsometry)
MURI 6/9/05

5. Imaging may involve spatial, spectral, and/or polarization effects
Source or
R(z )
Ranging
Detector
Axial imaging or
(x,y,z)
3D Imaging
Subsurface imaging
Imaging may involve spatial, spectral, and/or polarization effects
MURI 6/9/05

6. Optical Lithography
= Fabrication of objects with specified spatial distributions (2D, 3D) by use of optical sources and systems
Source
R(x,y)
Source
(x,y,z)
MURI 6/9/05

7. Limitations of Optical Imaging & Lithography
Resolution (transverse & axial)
Noise
Quantum
Classical
Io = RIi
Source Ii Io
Detector R
MURI 6/9/05

8. Quantum Imaging Quantum Lithography
= Estimation of the spatial distribution of a physical object
by use of light field in a nonclassical state & direct or
Interferometric measurement
Quantum Lithography
= Fabrication of objects with specified spatial distribution
by use of light field in a nonclassical state
MURI 6/9/05

9. States of Light Nonclassical States Coherent (laser imaging)
Thermal (conventional, photon-correlation imaging) …
Saleh et al. PRA 2000
Saleh et al. PRL 2005
Nonclassical States
Quadrature-Squeezed
Photon-Number Squeezed
Two-Photon
Gaussian
NOON …
MURI 6/9/05

10. Outline
Quantum Imaging
Two-Photon Imaging
Quantum OCT
MURI 6/9/05

11. non-separable function  entangled state
Two-Photon light 1 k1 2 k
= a state of exactly two photons in multimodes (spatial/spectral/polarization)
non-separable function  entangled state
Entanglement: Spatial (momentum)
Spectral
Polarization
MURI 6/9/05

12. H = Spatial, spectral, or polarization system
Two Configurations H r x
A. Direct H o H r x
B. Interferometric H o
H = Spatial, spectral, or polarization system
MURI 6/9/05

13. A. Applications of Direct 2-Photon Imagingx H o
MURI 6/9/05

14. 1. Correlated-Photon Absolute Measurement
Measurement of reflectance/ Transmittance/ Quantum Efficiency x
Sample
Klyshko, SJQE 77
Branning et al. PRA 00 x
Sample
Ellipsometry
Toussaint et al. PRA 04
SU(2) P A
MURI 6/9/05

15. 2. Imaging (transverse) - Spatial modesx
Belinskii & Klyshko, Zh. Eksp. Teor. Fiz. 94
Pittman et al., PRA 95
MURI 6/9/05

16. Example: Optical Fourier transform
3. Two-Photon Microscopy / Lithography
2-photon absorber
Factor of 2 enhancement
Abouraddy et al., JOSA-B 02
Boto et al., PRL 00
Example: Optical Fourier transform
Teich & Saleh, Cesk. Cas. Fyz. 97
MURI 6/9/05

17. 4. Dispersion Compensation
Hr() x C
Ho()
GVD’s of opposite signs cancel
Franson PRA 1992
MURI 6/9/05

18. B. Applications of Interferometric 2-Photon Imagingx H o
MURI 6/9/05

19. Axial Imaging/Ranging
Spectral Modes
Hr() x C
Ho()
i.e., insensitive to even-order dispersion (GVD) in Ho,
Interference term in C 
Nonlocal Dispersion Cancellation
Steinberg, Kwiat, Chiao, PRL 92; PRA 92
Shapiro, Sun, JOSA-B 94
Larchuk, Teich, Saleh, PRA 95
MURI 6/9/05

20. Outline
Quantum Imaging
Two-Photon Imaging
Quantum OCT
MURI 6/9/05

21. Q-OCT = Two-Photon Axial Imagingz
C()
Dispersion-Cancellation 
Hong-Ou-Mandel Interferometer
Abouraddy et al. PRA, , 2002
MURI 6/9/05

22. Experiment ct C(t) I(t) Kr+ 406 nm 55 mW x
Detector
Filter
2.2 mm
55 mW
Filter
NLC
8-mm LiIO3
Detector
Kr+ 406 nm
Sample
Nasr et al. PRL, 91, August 2003
MURI 6/9/05

23. Two Boundaries + dispersive layer
5-mm ZnSe
Air
90 m fused silica
Air
53 m
Classical
Quantum
19 m
MURI 6/9/05

24. M. B. Nasr et al., Opt. Express 12, 1353-1362 (2004)
Four Boundaries + dispersive medium in-between
90-m
AIR
12-mm
ZnSe
AIR
90-m
M. B. Nasr et al., Opt. Express 12, (2004)
MURI 6/9/05

25. The Promise of Q-OCT
Q-OCT promises x2 improved axial resolution in comparison with conventional OCT for sources of same spectral bandwidth
Self-interference at each boundary is immune to GVD introduced by upper layers
Inter-boundary interference is sensitive to dispersion of inter-boundary layers; dispersion parameters can thus be estimated
Preliminary experiments demonstrated viability of technique
Technique can be extended to transverse imaging (Q-OCM)
Technique can be extended to polarization-sensitive Q-OCT
MURI 6/9/05

26. Q-OCT: Challenges & Plans
State-of-the-art linewidth is not sufficiently large
(Axial resolution is only 19 m).
Two-photon flux is low. Duration of experiment is too long.
A better 2-photon source is needed!
Faster broadband single-photon detector is needed!
Applications to scattering media (e.g., tissue).
Theoretical & experimental research is necessary.
Algorithms for data processing need to be developed.
MURI 6/9/05

27. Reprints
MURI 6/9/05

28. Comparison of OCT & QOCT10 20 30 40 50 60 70
Penetration Length
in H2O
Resolution (m)
SLD  = 26 nm
SLD  = 61 nm
Ti:Al2O3,  = 140 nm
OCT
o = 812 nm
Cornea
Anterior
segment
Posterior
in Ocular Imaging
Eye 5 15 25 mm
better
8-mm LiIO3
 = 12 nm
QOCT
1-mm LiIO3,  = 60 nm
& QOCT
MURI 6/9/05