Nonlinear frequency conversion of vector beams with four wave mixing in atomic vapor

Abstract

We experimentally investigate the frequency conversion of vector beams with four-wave-mixing (FWM) in rubidium vapor. The conversion of vector beams from the probe beam to the conjugate beam is realized. In FWM experiments, the pump and the probe beam have orthogonal polarizations because of the polarization sensitivity of the FWM process and detection convenience. In order to satisfy the polarization sensitive phase matching condition and realize the nonlinear frequency conversion of vector beams, a Sagnac interferometer is used to form two FWM processes in the same rubidium cell, and two generated conjugate beams are combined with a polarizing beam splitter to form a conjugate vector beam. The experimental results agree well with our theoretical simulation. Compared with nonlinear optical crystals, the atomic vapor provides another platform to control and manipulate the vector beams nonlinearly.