The observation of the competition and suppression for stimulated Raman scattering near the potassium 4S-5P resonance

The competition of stimulated Raman scattering (SRS) between 4S-(5P)-5S and 4S-(3D)-5S channels has been observed as a laser is tuned near the 4S-5P r esonance in potassium vapour. The experimental results show that SRS only o ccurs in the 4S-(5P)-5S channel. In this Raman scattering, suppression of t he amplified spontaneous emission (ASE) (5S-4P) has been observed, The infl uence of the four-wave mixing (FWM) processes on the SRS is discussed. In t he 4S-(5P)-3D channel, in the backward direction no detectable emission cor responding to SRS (4S-(5P)-3D) has been observed, so the forward (5P)-3D em ission should be FWM, not SRS. The ASE (3D-4P) arises from the ASE (5P-3D), which can be observed in the backward direction.