Optical absorption of solids under laser irradiation

Abstract

Little attention has been paid so far on the effects produced on the electronic structure of solids by intense electromagnetic fields. Since the latter is of fundamental interest in interpreting a number of physical properties of solids, it would seem necessary to delineate and evaluate properly such effects both theoretically and experimen tally. It is the object of this paper to specifically examine this problem. In particular, it will be shown that band-gaps are opened in k-space regions where direct transitions occur. The resulting perturbations of the optical spectra of the laser irradiated solids will be discussed, comparison with existing data will be drawn, and meaningful experiments which have yet to be performed will be outlined.