A system for optically inspection one or more samples includes a sample stage, a laser system configured for illuminating a portion of the surface of the one or more samples disposed on the sample stage, and a detector configured to receive at least a portion of illumination reflected from the surface of the sample. The laser system includes an NLO crystal annealed within a selected temperature range. In addition, the NLO crystal is passivated with at least one of hydrogen, deuterium, a hydrogen-containing compound or a deuterium-containing compound to a selected passivation level. Further, the laser system includes a light source configured to generate light of a selected wavelength. The light source is configured to transmit light through the NLO crystal. The laser system includes a crystal housing unit configured to house the NLO crystal.