Development in Laser Induced Extrinsic Absorption Damage Mechanism of Dielectric Films

Absorption of host and the temperature-dependence of absorption coefficient have been considered in valuating temperature distribution in films, when laser pulse irradiates on films. Absorption of dielectric materials experience three stages with the increase of temperature: multi-photon absorption; single photon absorption; metallic absorption. These different absorption mechanisms correspond to different band gap energies of materials, which will decrease when the temperature of materials increases. Evaluating results indicate that absorption of host increases rapidly when the laser pulse will be over. If absorption of host and the temperature-dependence of absorption are considered, the maximal temperatures in films will be increased by a factor of four.