Observation of four-wave mixing in caesium atoms using a noncycling transition

In this paper the generation of four-wave mixing (FWM) signal using a noncycling transition of caesium atoms is investigated when the pumping laser is locked to the transition 6\rm S_1/2F=4\to6\rm P_3/2F'=4, and meanwhile the probe frequency is scanned across the 6\rm S_1/2F=4 \to6\rm P_3/2 transition. The efficiency of the four-wave mixing signal as a function of the intensity of the pumping beams and the detuning of the pumping beams is also studied. In order to increase the detection efficiency, a repumping laser which is resonant with 6\rm S_1/2 F=3\to 6\rm P_3/2F'=4 transition is used. A theoretical model is also introduced, and the theoretical results are in qualitative agreement with experimental ones.