Influence of the mode composition of laser radiation on the optical breakdown of silicate glasses

An investigation was made of the influence of the number of longitudinal and transverse modes in the radiation emitted by a neodymium laser on the statistical characteristics of optical breakdown of K8 and TF10 glasses. The statistical nature of the bulk optical breakdown in these glasses was governed primarily by the statistics of the incident laser radiation, whereas in the case of surface breakdown it was governed by the statistics of surface defects. It was found that there was no statistical scatter of the breakdown threshold when radiation with a single longitudinal and a single transverse mode interacted with the bulk of a glass sample.