Terahertz emitting and four wave mixing details in 6P3/2→11DJ pumped cesium vapor

Terahertz emitting and FWM (Four wave mixing) processes in 6P_3/2→11D_J near-resonating pumped cesium vapor are studied in this work. Using a nanosecond 550 nm pump laser, collimated frequency converted lights around 557 nm and 563 nm are observed in cesium vapor. A detailed analysis shows that the frequency converted lights come from FWM processes driven by the pump laser and stimulated terahertz emissions in the frequency range of 1-7 THz. These stimulated terahertz emissions are generated by cesium atom SERS (stimulated electronic Raman scattering) or ASE (amplified spontaneous emission) under pumping. The terahertz emission iQEs (internal quantum efficiency) are estimated to be on the order of 1 E -3 ~ 1 E -2 as their lower limits. Results of this work will contribute to studies on atom FWM physics, terahertz light source and detector based on atom vapor.