OPTICAL BISTABILITY AND TRANSVERSE INHOMOGENEITIES IN DIFFUSIVE SYSTEMS WITH INDUCED ABSORPTION

In this contribution the systematic analysis of the steady-state absor ptive optical bistability in a thin semiconductor film is given. The h eat-conductivity equation with corresponding two-point boundary condit ions is solved numerically and the analytical approximation of the swi tching intensity is given based on the theorem about lower bounds for critical parameters in nonlinear boundary-value problems. The influenc es of diffusion and of spatial inhomogenities of the excitation profil es in the sample on the input-output characteristic are analyzed in de tail. The transverse nonuniformity of the system leads to a condition for the existence of bistability that differs significantly from the w ell known case of a spatially homogeneous excitation of the medium. Th e critical slowing down phenomenon is discussed analytically and compa red to previous experimental results.