Scaling in damage of optical materials by intensive laser radiation

Abstract

This is a short review of the main reasons of the laser induced damage space scaling, when damage is caused by the first laser shoot (1-on-1) and by the sequence of N laser pulses to one and the same place (N-on-1). It is shown that the laser pulse shape is important to laser damage and scaling in some cases. The accumulation of material property changes and LID threshold for N-on-1 process has strong dependence on the front and on the back pulse slopes: the material property remnant changes become les and eventually accumulative damage disappears when the pulse slopes are increased. When damage scaling is defined by competition of the self-focusing and SBS processes, the long front slope is favored to SBS. The theoretical model explains damage from the first laser shot (1-on-1), damage from sequence of laser pulses (N-on-1 LID), accumulation and damage scaling. The volume damage of transparent dielectrics by laser radiation, when photon energy is more then twice less material ionization (hν