OPTICAL BISTABILITY IN ZINC-SULFIDE AND ZINC-SELENIDE THIN-FILM INTERFERENCE FILTERS AND IN GALLIUM-ARSENIDE AND COPPER-CHLORIDE ETALONS (NONLINEAR).

摘要

Two-photon optical bistability in commercial thin-film interference filters with ZnS and ZnSe spacers is observed with switching times ≳ 200 μs. The accompanying drifting of the bistability loop in time and laser-induced "damage" indicate a thermal mechanism. The problem of water vapor absorption in such filters must be addressed before the inherent potential and advantages of these devices in two-dimensional image processing applications can be realized. Trans- verse effects in GaAs superlattice etalons are observed which cannot be explained on the basis of a plane-wave analysis. The optical nonlinearity in GaAs and diffraction combine to produce drastic effects on the measured beam profiles and bistable loops, due to an intensity-dependent virtual focus. Lastly, the first observation of optical bistability due to a biexcitonic nonlinearity in CuCl etalons is reported with detector-limited switching times of 600 ps. In addition, lasing action along the pump axis in a cavity defined by the end mirrors is observed in a very thin (2.0 μm) CuCl etalon. The lasing transition is unique in that it involves the creation of a virtual excitation of biexcitons which decay to the longitudinal exciton state.