Mixing of terahertz and near-infrared radiation in quantum wells in strong magnetic fields

It was recently discovered that undoped GaAs quantum wells illuminated simultaneously by near-infrared (NIR) and THz radiation in strong magnetic fields emit sharp, strong sidebands [Kono et al., Phys. Rev. Lett. 79 (1997) 1758]. We developed a perturbative theory, based on a magnetoexciton model, for this phenomenon and obtained the optical susceptibility. The theoretical results semiquantitatively explain all the experimental results. Moreover, the theory has revealed how the sideband resonances can be related to intra-exciton transitions, indicating the usefulness of the sideband generation as a new tool of magnetoexciton spectroscopy. (C) 1998 Elsevier Science B.V. All rights reserved.