Multi-photon absorption spectra involving the magneto-optical and Wannier - Stark effects in superlattices

Abstract

The interband multi-photon absorption spectrum from a semiconductor superlattice induced by an intense optical wave in the presence of uniform magnetic and electric fields is analysed theoretically. The oscillating electric field of the optical wave and the uniform electric and magnetic fields are all directed perpendicular to the heteroplanes. The explicit dependences of the coefficient of the multi-photon absorption on the frequency and magnitude of the oscillating electric field, on the superlattice parameters and on the magnitudes of the uniform electric and magnetic fields are obtained. The uniform electric field is assumed to be sufficiently strong to provide Wannier - Stark localization of the carriers. The electron - hole cyclotron frequency and the frequency of the Stark oscillations are taken to be commensurate with their ratio being rational. It is shown that, under these conditions and in contrast to one-photon spectra, an enhancement of the series of resonances could arise. It is also shown that the form of the spectrum depends on the relationship between the cyclotron and Stark frequencies and on the number of photons involved.