Laser-induced inclusion damage at surfaces of transparent dielectrics

Abstract

Q-switched laser-induced damage to transparent surfaces is shown to occur in many cases without the formation of a bright plasma. This ``aplasmic'' damage is apparently due to absorption by submicron inclusions. The prominence of damage is a function of material, polishing compound, and geometry of the test situation. Because aplasmic damage can be difficult to detect, it is suggested that the results of experiments conducted with small beams, especially when plasma formation is used as a definition of damage, be interpreted with caution. Damage thresholds of several materials are reported incidentally.