Laser induced lattice strains and damage threshold limitation due to lattice defects in transparent optical materials

Abstract

The interaction of a high power laser beam with the lattice of transparent optical materials induces internal strains in the latter. Attention is focused on optical materials of zinc blende structure and excitation at the 10.6-microm wavelength of the laser. A lattice dynamical technique, which utilizes the imperfect lattice Green's functions, is used to calculate the expected magnitude of the actual strains induced in real crystals taking into account the effect of lattice point defects. The information on the elastic strength of these materials then enables the quantitative evaluation of laser induced mechanical damage thresholds in very good agreement with the available state-of-the-art figures.