Theory of increasing absorption optical bistability and self-focusing in bulk ZnSe

Absorptive optical bistable behavior in a ZnSe semiconductor has been experimentally investigated in a few publications in the past years; however, its physical mechanism has not been explained theoretically. In the present paper, we propose a theoretical model for absorptive optical bistability, with and without self-focusing, in bulk ZnSe at room temperature and at a power of about 80-300 mW for the visible wavelength of 476 nm. This theory is based on the nonlinear variation of the temperature-dependent absorption coefficient near the band edge. In this work we, with the help of graphical methods, obtained several theoretical input-output curves, showing a hysteresis loop, that clearly reproduce the main qualitative features of the experiments with generally good quantitative agreement.