Effects of laser beams on laser components

The destruction of laser components by the high-power light is a major obstacle to the use of lasers of extremely high power. Two kinds of laser-induced damage, a form of nonlinear optics, are discussed. The first kind involves the damage due to the absorption of energy by small particulate inclusions or impurities in the material. The small particles absorb energy from the laser beam and explode, damaging the material in the vicinity. The second category of damage - intrinsic damage - results from the inability of a pure material to withstand the high-power densities of a Q-switched or mode-locked laser pulse. The 100 million-watt peak-power laser pulse from a Q-switched laser can produce an oscillating electric field of the order of several million volts per centimeter, which is strong enough to cause permanent damage to inclusion-free material. Several features of laser-induced damage are discussed.