IMPURITY-RELATED DYNAMICAL OPTICAL SWITCHING IN CDS

Nonlinear optical transmission in unintentionally or lightly doped CdS crystals is studied theoretically and experimentally near the band ga p. A spatially homogeneous three-level model is developed which explai ns the observed optical switching process and its dependence upon inci dent intensity, wavelength, lattice temperature, and surface reflectiv ity. It is shown that the switching is due to the dynamics of the gene ration-recombination processes involving donors, accepters, and the co nduction band: and not due to transmissive optical bistability.