Cavity-free optical bistability in a thin semiconductor film when excitons and biexcitons are generated

A theoretical investigation is reported of steady-state nonlinear transmission of resonant laser radiation by a thin semiconductor film under the conditions of two-pulse generation of excitons and biexcitons. The equations of state are derived for the description of bistable behaviour of the amplitudes of the transmitted pulses and of the quasiparticle concentration, depending on the parameters of the exciting fields. The criteria of existence of an optical bistability are determined.