Intense-field effects in solids

Abstract
The interaction of solids with electromagnetic radiation is investigated using nonconventional theoretical techniques. Interband transitions in solids are investigated with a Volkov-type wave function used to represent the conduction-band electron in a calculation of the multiphoton interband transition rate induced by circularly polarized electromagnetic radiation of arbitrary intensity. The behavior of the transition rate is shown to be identical to that obtained from perturbation theory in the low-intensity domain, but deviates sharply from conventional weak-field characteristics for high intensities. Intense-field behavior in solids is found to have an earlier onset than in atoms.