Role of absorbing defects in the mechanism of laser damage of real transparent dielectrics

An investigation was made of the volume damage of sapphire and quartz crystals and of optical glasses of various kinds by laser pulses of 1–7 nsec duration. The roles of microscopic absorbing defects and of the self-focusing effect in the damage process were analyzed. It was found that they dominated the damage which occurred in real transparent media. This led to the proposal and study of a criterion of the optical purity of transparent dielectrics based on a comparison of the intensities of the Rayleigh and Brillouin scattering of light.