Mechanism of optical breakdown in transparent dielectrics

An experimental investigation was made on the dependence of the optical breakdown threshold of various organic liquids on their purity. It was found that the optical strength of a liquid could be increased by two orders of magnitude by the removal of "mechanical" impurities. It was concluded that the optical strength of laser resonator elements was governed by the presence of absorbing microparticles in the bulk and, particularly, on the surfaces of these elements.