Unexpected irreversible damage of an asymmetric bismuth silicate photorefractive spatial light modulator

Unexpected irreversible damage occurred repeatedly in the asymmetric bismuth silicate (BSO) photorefractive spatial light modulator under some operation modes, even though the power of the write-light beam does not exceed the optical damage threshold. According to the microscopic surface images and the Raman spectra of the BSO film, sudden rising of temperature in local areas caused by the drift of the photon-induced electrons is responsible for the damage; the damage exists not only on the surface but also inside the BSO crystal. The damage is relative to the structure of the spatial light modulator, the operation mode, and the growth of the BSO crystal. The information provided by the damage is useful for optimizing the structure, the operation modes, and the performance of the photorefractive spatial light modulators.