MULTIPHOTON ABSORPTION-SPECTRA INVOLVING THE MAGNETOOPTICAL AND WANNIER-STARK EFFECTS IN SUPERLATTICES

The interband multi-photon absorption spectrum from a semiconductor su perlattice induced by an intense optical wave in the presence of unifo rm magnetic and electric fields is analysed theoretically. The oscilla ting electric held of the optical wave and the uniform electric and ma gnetic 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 held, on t he superlattice parameters and on the magnitudes of the uniform electr ic and magnetic fields are obtained. The uniform electric field is ass umed to be sufficiently strong to provide Wannier-Stark localization o f the carriers. The electron-hole cyclotron frequency and the frequenc y of the Stark oscillations are taken to be commensurate with their ra tio being rational. It is shown that, under these conditions and in co ntrast to one-photon spectra, an enhancement of the series of resonanc es could arise. It is also shown that the form of the spectrum depends on the relationship between the cyclotron and Stark frequencies and o n the number of photons involved.