Exciton-exciton interaction and absorption bistability in CdS at low optical excitation levels
Dneprovskii V. S. , Klimov V. I. , Nazvanova E. V. , Furtichev A. I.
A sharp decrease has been observed in the transmission near the fundamental absorption edge of CdS crystals (80 K) at low levels of the excitation by the beam from an argon laser (below 10 kW/cm2). An absorption bistability has been detected under the same conditions. Analysis of luminescence spectra reveals that the rapid change in the nonlinear absorption which occurs in the crystals during such an excitation is a consequence of an exciton-exciton interaction.