OBSERVATION OF THE SUPPRESSION OF THE STIMULATED HYPER-RAMAN SCATTERING (S-3(1/2)-P-4(3/2)) NEAR THE SODIUM 4D 2-PHOTON RESONANCE

Abstract

The stimulated hyper-Raman scattering (SHRS) emissions associated with the excitation of the 4P(3/2) state in sodium vapour have been observed in both the forward and backward directions as the pumping laser was tuned near the 3S-4D two-photon resonance. The results show that though the forward SHRS process is greatly reduced by a destructive interference between it and the four-wave mixing (FWM) process induced by itself, the forward SHRS emission has a positive gain and can still be observed under a certain condition.