THEORY OF THE LASER BREAKDOWN OF OPTICAL DIELECTRIC COATINGS, CAUSED BY ABSORBING INCLUSIONS

This paper analyzes the mechanisms of the laser breakdown of thin insu lating films. The problem of the breakdown of a single-layer coating i nitiated by an absorbing inclusion is treated. It is established that the dependence of the laser breakdown threshold of coatings on the ban dgap of the coating material plays a fundamental role. The other manif estations of the coating breakdown-the dependence of the breakdown thr eshold on the coating thickness and on the position of the inclusion i n the region of the coating-are a consequence of the dependence of the breakdown threshold on the bandgap of the coating material. The resul ting dependences of the breakdown threshold on the coating parameters explain the experimentally observed regularities. (C) 1996 The Optical Society of America.