Abstract

The basic physical principles of laser-solid interactions start with the absorption of light by electrons. In semiconductors electron-hole pairs are created, and for intense laser pulses their concentration may approach that of a metallic conductor. For both metals and semiconductors the hot plasma acquires a common electron temperature T_e. since carrier-carrier collisions produce a rapid equilibrization on time scales of 10⁻¹⁴ sec for N >10²⁰ cm⁻³. In the next step energy is transferred from the plasma to the lattice. The time constant for this process is estimated to lie between 10⁻¹² and 10⁻¹¹ sec for most metals at lattice temperatures above 77 K. Most theoretical estimates yield similar time constants for hot electrons in semiconductors based on reasonable values of the deformation interaction potential. In GaAs the rapid decrease of electron energy by a cascade of optical phonon emission is well established. It has been suggested, however, that for silicon and germanium the time constant for energy transfer to the lattice may be much longer.

© 1981 Optical Society of America