OPTICAL BISTABILITY AND TRANSVERSE INHOMOGENITIES IN DIFFUSIVE SYSTEMS WITH INDUCED ABSORPTION

In this contribution the systematic analysis of the steady-state absorptive optical bistability in a thin semiconductor film is given. The heat-conductivity equation with corresponding two-point boundary conditions is solved numerically and the analytical approximation of the switching intensity is given based on the theorem about lower bounds for critical parameters in nonlinear boundary-value problems. The influences of diffusion and of spatial inhomogenities of the excitation profiles in the sample on the input-output characteristic are analyzed in detail. The transverse nonuniformity of the system leads to a condition for the existence of bistability that differs significantly from the well known case of a spatially homogeneous excitation of the medium. The critical slowing down phenomenon is discussed analytically and compared to previous experimental results.