Theory and modeling of laser-induced free-electron heating in wide-gap solids

Abstract

A microscopic theory for the interaction of intense laser radiation at visible and near-infrared wavelengths with free electrons in a wide-band-gap solid is presented. We calculate the free- electron mediated energy transfer from the laser field to the solid and the electron- multiplication rate due to band-to-band ionization as a function of laser intensity at wavelengths in the range 250 nm (lambda) &lt; 10 micrometers , using SiO<SUB>2</SUB> as an example. The formalism is based on a Monte Carlo integration of the Boltzmann transport equation. The interaction of the laser radiation with the free electrons is treated both within the standard classical approximation and quantum mechanically using second-order perturbation theory. Steady state Monte Carlo results are used in rate equations to make a direct comparison to experimental laser-induced heating data.