Multiphoton intraband absorption of electromagnetic waves and stimulated scattering by optical phonons in the superlattice

Abstract

Multiphoton intraminiband absorption of the electromagnetic wave and stimulated scattering by optical phonons in the semiconductor superlattice are considered. The absorption coefficient is found without using the quantum kinetic equation. The absorbed energy is plotted versus the electric field of the wave. It is found that, as the electric field grows, the absorbed energy reaches a maximum and then starts decreasing in an oscillatory manner. An explanation for such a run of the absorbed energy with electric field is given. It is shown that multiphoton absorption must be taken into account if the condition eEd ≥ ℏω is satisfied. Stimulated multiphoton scattering by optical phonons in superlattices is shown to produce harmonics of the scattered light at frequencies both higher and lower than those of the incident light. Scattering partial cross sections are found and plotted versus the incident wave intensity.