Laboratory of Optical Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China; Department of Physics, Hebei University, Baoding 071002, China
Abstract:
Two-photon resonant nondegenerate four-wave mixing (NFWM) with theaddition of a coupling field in Ba atomic vapour has been studied. Wefind that coherence of the atomic level transitions leads tosuppression of the NFWM signal, giving rise to a dip with a linewidththat is linearly proportional to the intensity of the coupling field.