Thermoelastic stresses generated in solid transparent dielectrics by a focused laser beam

A theoretical analysis is made of the thermoelastic stresses generated in a solid optically transparent isotropic homogeneous dielectric by laser radiation focused in the interior of this dielectric by an optical system. An allowance is made for the thermal conductivity of the dielectric and for the dynamics of the stresses. The absence of self-focusing is assumed in the derivation of a general expression for the thermoelastic stresses and for the critical value of the radiation power density at which damage occurs at the focus of the optical system. If the response of the dielectric is instantaneous and if self-focusing does take place, the nature of the damage is found to depend strongly on whether the absorption of the laser radiation is linear or nonlinear. It is shown that the self-focusing of the laser radiation should always result in damage if the dielectric absorbs nonlinearly.