Behavior of laser induced emission intensity versus laser power density during breakdown of optical materials

Abstract

Breakdown in Si02 is studied versus fluence using an intensified CCD spectrometer. Broad-band photoluminescence spectra were measured versus number of laser pulses. Before the breakdown of fused silica, the intensity of this photoluminescence increases. After breakdown, a plasma is formed and ablated Si emission lines are measured. The plasma is characterized by its emission spectra and excitation temperature temporal profiles. The temperature profiles of the plasma are calculated by the Bolzmann method. These data are studied to provide fundamental information on breakdown mechanisms in optical materials.