Kinetics of photoinduced optical anisotropy in oxide glass

Long-lived optical anisotropy generated in glasses by bichromatic mutually coherent radiation is associated with the accumulation of a built-in electric field. The kinetics of photoinduced anisotropy was studied within the framework of a phenomenological model taking into account the polarization-and current-induced mechanisms of field formation and the medium conductivity. The combination of the current and polarization mechanisms gives rise to new effects. The accumulation of anisotropy and its dark relaxation have a nonmonotonic character. For a sufficiently high and rapidly relaxing photoconductivity, «hidden writing» is possible, for which the anisotropy is absent during the course of bichromatic illumination, but it appears after switching off the light and relaxes slowly due to dark conduction.