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Tallinn University of Technology Institute of Cybernetics Propagation characteristics of coherent optical waves in a stratified medium with Kerr nonlinearity

The propagation of coherent light through a nonlinear periodic optical structure with periodic linear and nonlinear refractive indices is studied. Nonlinear coupled mode equations are derived from Maxwell equations to investigate input-output transmission regimes of optical structures. Both stable and multi-stable behavior are analyzed including alloptical limiting — highly nonlinear stable transmission with monotonic and one-to-one input-output power relationship that has upper threshold value. Periodic optical structures can be applied in optical communication systems as uniform switches, logic elements, or optical limiters. In Chapter 6 this theory is applied to CdSe-nanoparticles dispersed photopolymer holograms. We consider four different index distributions and find that all of them exhibit globally multi-stable behavior. Such structures are usually applied as switching devices between lower-transmissive and higher-transmissive states. We have shown that multistable behaviour at very low intensities can be achieved in given structure, especially for longer gratings. Limiting behavior could be achieved by using different intensities for hologram recording, or changing the angle between the writing beams.