Intrinsic and multiple pulse laser-induced damage of transparent dielectrics in the femto-nanosecond region

This review is devoted to a long-term investigation into the nature of the laser-induced damage of silicate glasses. Besides damage threshold measurements, it includes data about linear and nonlinear absorption, multiple pulse damage, and subthreshold modification of media. The experiments were carried out over a wide range of wavelengths, pulse durations, and spot sizes. As an important result, we show that the threshold power density of the intrinsic damage of the boro-silicate glass at similar to1 mum wavelength does not depend on pulse duration from 2 x 10(-13) to 3x 10(-8) s as long as self-focusing is avoided. This result cannot be explained by existing theories and indicates that the damage mechanism involves a collective response of a certain volume in the dielectric as a whole, rather than the accumulation of electrons via individual generation processes, like multiphoton, tunneling, or avalanche. Special attention in the research was paid to investigation into the processes of electron excitation in alkali- and lead-silicate glasses.