THz emission from photoexcited semiconductor superlattices with applied AC and DC electric fields

Summary form only given. The numerical investigations are based on a microscopic many-body theory which allows one to compute the linear and nonlinear optical properties of semiconductor superlattices in the presence of homogeneous electric fields applied in the growth direction. The THz-emission due to the field-driven dynamics of photoexcited carriers is investigated for the combined action of static and alternating fields. The applied field is written as F(t)=F/sub 0/+F/sub 1/ cos(/spl omega//sub L/t). For such a driving field it was shown within a simple model that the equations governing the intraband dynamics in the field-driven superlattice should be analogous to the ones describing the superconducting Josephson junction. The transport properties in this regime can be described by the picture of multi-photon-assisted tunneling between Wannier-Stark states. It is shown that the THz-emission spectroscopy gives direct access to transport in this regime.