Radiation of THz electromagnetic waves from oscillating exciton population in semiconductor microcavities

Abstract

Summary form only given. Cavity-induced exciton-polaritons formed in high-Q semiconductor microcavities (SMCs) are attracting a lot of interest from viewpoints of fundamental physics and application. So far, either coherent or incoherent dynamics of cavity-polaritons after short pulse excitation have been investigated mostly through the photonic part of the polaritons, i.e. the light emission from SMCs. On the exciton part, there have been a few works utilizing the four wave mixing (FWM) technique, where some complexities arise in the analysis of the results, and the origin of the oscillation in the FWM signals is a subject of current interest. On the other hand, when a static electric field, E/sub QW/, is applied to the quantum well (QW), the excitons are polarized and the oscillation of exciton population is expected to radiate an electromagnetic wave (EMW). Since the EMW radiation is a result of optical rectification, a second order nonlinear process, it provides a direct information on the coherent dynamics of exciton population. In typical SMCs, the frequency of the EMW, roughly given by the spectral polariton mode splitting /spl Omega//sub p/, is in THz range.