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Light deflection and modulation through dynamic evolution of photoinduced waveguides.
Germano Montemezzani1, Mohamed Gorram, Nicolas Fressengeas
1Laboratoire Matériaux Optiques, Photonique et Systèmes University Paul Verlaine-Metz and Supelec, CNRS UMR 7132, Metz, France. germano.montemezzani@metz.supelec.fr
Optics Express
|October 15, 2008
Summary
Light-induced waveguides in photorefractive crystals can be dynamically controlled after illumination. This allows for significant deflection and modulation of guided light by manipulating space charge distributions.
Area of Science:
- Photorefractive materials
- Nonlinear optics
- Waveguide optics
Background:
- Light-induced waveguides in photorefractive crystals are typically sustained by an applied electric field.
- The dynamic evolution of these waveguides after field removal is not fully understood.
- Space charge screening and counter-screening effects play a role in photorefractive phenomena.
Purpose of the Study:
- To investigate the dynamic evolution of light-induced waveguides in photorefractive crystals after removal of the applied electric field.
- To demonstrate the deflection and modulation of guided light using these dynamic waveguide evolutions.
- To analyze the role of space charge distribution in controlling guided light.
Main Methods:
- Fabrication of light-induced waveguides in photorefractive crystals via lateral illumination.
- Removal of the sustaining applied electric field to observe waveguide dynamics.
- Utilizing space charge screening and counter-screening effects for light manipulation.
- Numerical simulations of refractive index evolution and beam propagation.
Main Results:
- Observed complex dynamic evolution of waveguides upon electric field removal.
- Achieved deflection and modulation of guided light by exploiting space charge dynamics.
- Demonstrated significant spot separation upon deflection, exceeding 10 times the waveguide width.
- Numerical simulations showed good agreement with experimental observations.
Conclusions:
- The dynamic evolution of photorefractive waveguides offers a controllable method for light manipulation.
- Space charge screening and counter-screening are key mechanisms for deflection and modulation.
- This effect has potential applications in optical switching and signal processing.
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