Study of the surface damage threshold and mechanism of KDP crystal under ultrashort laser irradiation

Abstract

Here, we investigate the mechanism of surface damage threshold anisotropy induced by ultrashort laser in potassium dihydrogen phosphate (KDP) crystal. Carrier-lattice nonequilibrium interaction is simulated based on Brillouin light-scattering (BLS) spectroscopy and a complete self-consistent model to obtain the time evolution of carrier density and temperature as well as lattice temperature. The results indicate that the trend of the lattice temperature is consistent with the experimental phenomena. Meanwhile, the electron-phonon coupling effect, in addition to the electron density traditionally considered, is an important factor affecting damage and is a major contributor to the anisotropy of the damage threshold.