Size dependence of degenerate four-wave mixing signal due to enhancement of internal field in mesoscopic systems

Abstract

By means of the microscopic nonlocal theory of nonlinear response, we elucidate an anomalous size dependence of degenerate four-wave mixing (DFWM) signal for an ultra thin film confining the center-of-mass motion of excitons. In a mesoscopic thin film, a particular spatial pattern of the internal fields of both the incident and signal beams are doubly enhanced for the DFWM process at the resonance energy including the radiative shift. This can be a new mechanism for the large enhancement of the DFWM signal.