Avalanche breakdown and the probabilistic nature of laser-induced damage

This paper discusses the probabilistic nature of the damaging interaction between light and matter. It is shown that when one recognizes that there is some probability to induce damage at any level of optical irradiation, then the reported irreproducible damage-resistance properties of many useful materials can be understood. This point of view also explains why some optical components may be safely irradiated many times before damage occurs, though no other change in the material can be detected prior to the observation of damage. Experimental data showing the probability for surface damage as a function of power density are presented for several materials. The dependence of damage probability on optical field strength is similar to that of the dc ionization coefficients for semiconductors and gases on the applied field. This observation is discussed and it is suggested that a form of avalanche breakdown might be the cause of laser-induced damage.