Mechanism of bulk laser damage to CdS-type semiconductors

An investigation was made of the photoconductivity of pure CdS crystals at the moment of appearance of bulk damage and of the kinetics of this damage. An analysis of the experimental data revealed direct multiplication of carriers as a result of bulk damage, dependence of the bulk damage threshold on the amplitude of the optical wave field, and the instantaneous nature of the damage itself. This evidence shows that electron avalanche ionization is the dominant bulk damage mechanism in the case of pure CdS-type semiconductors subjected to nanosecond laser radiation pulses.