1 « Control of pattern formation in a single feedback system by photonic bandgap structures » Nicolas Marsal , Germano Montemezzani, Delphine Wolfersberger, Marc Sciamanna Lab. Matériaux Optiques, Photonique et Systèmes (CNRS - UMR 7132) Université Paul Verlaine - Metz and SUPELEC France Dragomir Neshev Nonlinear Physics Centre, Research School of Physical Sciences and Engineering, Australian National University, Canberra, Australia
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1 « Control of pattern formation in a single feedback system by photonic bandgap structures » Nicolas Marsal, Germano Montemezzani, Delphine Wolfersberger,
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1
« Control of pattern formation in a single feedback system by photonic bandgap
structures »
Nicolas Marsal, Germano Montemezzani, Delphine Wolfersberger, Marc SciamannaLab. Matériaux Optiques, Photonique et Systèmes (CNRS - UMR 7132)
Université Paul Verlaine - Metzand SUPELEC France
Dragomir NeshevNonlinear Physics Centre, Research School of Physical Sciences and Engineering,
Australian National University, Canberra, Australia
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1. Introduction to pattern and photonic lattice
2. Our experimental setup
3. Results
4. Conclusions
Outline
3
Pattern
Nonlinear medium
Free propagation
Single feedback
Linear cavity
Mirror
Photorefractive crystal, Kerr…
Liquid-crystal light valves (LCLV), Photorefractive crystal, Na vapors…
Lasers…
1. Patterns / photonic lattice
2. Setup
3. Results
4. Conclusions
Active medium
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Pattern : properties
• Light structures spatially modulated and correlated
• Generated thanks to noise and modulation instability
• Disordered or ordered geometry
Goal Control of pattern
1. Patterns / photonic lattice
2. Setup
3. Results
4. Conclusions
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Pattern : control
C. Denz, Ann. Phys. (Leipzig) 13, 391 (2004)
A.V. Mamaev, M. Saffman, Europhys. Lett. 34, 669 (1996)
C. Denz, Phys. Rev. Let. 81, 1614 (1998)
And with a photonic lattice … ?
R. Neubecker and A. Zimmermann, Phys. Rev. E 65, 035205 (2002)
E
Fourier Filter
External illumination
1. Patterns / photonic lattice
2. Setup
3. Results
4. Conclusions
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Photonic lattice
Light induced
photonic crystal
photonic crystal
Periodic illumination ( lattices or light
interferences )
Light sensitive medium ( photorefractive crystal )
Periodic variation of the refractive index inside the
medium
1. Patterns / photonic lattice
2. Setup
3. Results
4. Conclusions
Propertiesn1
n0
real space 1st and 2nd BZ
a
w = kc / n
Constant refractive index Periodic refractive index
Bandgap effect
2π / a
k space
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Experimental setup
1. Patterns / photonic lattice
2. Setup
3. Results
4. Conclusions
Goal Pattern control by a photonic lattice
MirrorPhotorefractive BaTiO3 crystal
Far field (k space)
External periodic illumination
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ff2
f2
f
BSP BS
Lattice
HWP
L1SF
LA
PC
2f 2f
LASER
FarField
M
L2
L3 L4
Horizontal polarization
Vertical polarization
4f system
M : Mirror
: Feedback loop
VM
BS : Beam SplitterHWP : Half Wave PlateBSP : Polarizing Beam Splitter L : Lens SF : Spatial Filter LA : Linear Atenuator PC : Photorefractive Crystal VM : Virtual Mirror