Abstract

In the parabolic-band effective-mass approximation model of a semiconductor, application of a magnetic field leads to the formation of equally spaced Landau levels. By application of a spectrally broad laser pulse, one would expect to observe in the coherent emission quantum beats with a periodic time dependence. In fact, in transient (100-fs) four-wave-mixing (FWM) experiments in GaAs, we observed nonperiodic multiple beating between magnetoexcitons associated with different Landau levels. This results from complex density-dependent quantum interferences between coupled slates in the material.¹

© 1994 Optical Society of America