Collective excitation of transparent dielectrics under femtosecond pulses

The goal of this work is to measure the intrinsic laser-induced damage (LID) of a borosilicate glass for femtosecond pulses and to compare it with data obtained for the nanopicosecond region under conditions when self-focusing is avoided. This study demonstrates that the intrinsic LID irradiance of industrial borosilicate glass does not depend on pulse duration for 2 /spl times/ 10/sup -13/ - 3 /spl times/ 10/sup -8/ s pulses. This finding is in favor of the LID mechanism, which is based on the phase transition scenario, rather than the currently accepted view based on a multi-photon ionization with ensuing avalanche development.