Results of analysis and comparison are given of the effects of spatial (mainly transversal) distribution in optical bistable systems (increasing absorption bistability, nonlinear resonators and nonlinear reflection) and in a system with phase transition (liquid - vapour).
Abstract Results are presented of a theoretical analysis of transverse and longitudinal distributivity effects in semiconductor optical bistable systems. For a resonatorless increasing absorption bistable system the kinetics of autopulsations (resulting from the formation of moving absorption domains) are described. For wideaperture nonlinear interferometers new types of field spatial structures are shown: immovable and moving autosolitons, waves of automodulation and autostochasticity, and pulsing distributions.
Optical bistability is a first-order nonequilibrium phase transition, which is characterized by the spatial or temporal coexistence of two phases. In systems with resonators this phase coexistence can be realized in the form of transverse patterns of high and low intensity values, whereas in a resonatorless optical bistability the phase coexistence becomes manifest in a longitudinal intensity variation. In systems in which strong diffusion of the elementary excitations suppresses spatial phase coexistence, random fluctuations establish at least in principal a temporal phase coexistence by stochastic switching between the two bistable states.
An analysis is made of nonlinear optical phenomena associated with a change in the orientation of the director of a liquid crystal induced by an optical field and resulting in optical bistability. The usual configurations with a nonlinear Fabry-Perot resonator and several other configurations are considered. Bistable cells with cholesterics are proposed: in these cells the nonlinearity is associated with the absorption of the incident and reflected light and is related—via the temperature of the cell—to the cholesteric helix period. Devices are considered in which switching from one state to another takes place as a result of a change in radiation parameters (such as the frequency or polarization) other than the power.