Real-time detection of laser damage threshold of AR coating of high-power optics

Abstract

A photorefractive dynamic Schlieren (PDS) system is designed to monitor the photothermal damage-threshold of ZrSiO2. The PDS is calibrated by observing the fringe movement in a Twyman-Green interferometer (TGI). While the phase changes due to optical path difference (OPD) of about (gamma) /10 are detectable by TGI, the PDS is capable of revealing intensity changes due to OPD of less than (gamma) /20. In this experiment a Nd:YAG laser is the source for photothermal phase change while a HeCd provides the Schlieren field.