Interaction of THz transients and ultrashort optical pulses in quantum wells: anisotropic wavepackets and optical switches

Summary form only given. With the advancement of free-electron lasers as well as THz solid-state emitters, THz physics and related technology is emerging out of its infancy. Two-color techniques (optical and THz) applied to mesoscopic semiconductors have also recently been developed. Consequently, the dynamics of charge carriers (electrons and holes) after excitation with short light pulses and THz fields in semiconductor heterostructures has been receiving an upsurge of attention recently. We investigate the physics and applications of interplaying optical (interband) and THz (intraband) fields in a quantum well (QW). Our theoretical approach is based on a nonperturbative, numerical solution of the anisotropic semiconductor Bloch equations. We study InGaAs-QWs excited by realistic optical and THz fields with arbitrary polarizations. New and intriguing carrier dynamics emerge, and a series of relative motion electron-hole (e-h) wavepackets (WPs) are depicted and analysed, as is a new scheme for efficient ultrahigh-speed optical switching in a semiconductor optical amplifier (SOA).