Generation of coherent blue light via bichromatic pumping in cesium vapor

Diode-pumped alkali lasers, possessing high efficiency and narrow linewidth, can provide feasible solutions for wavelength ranges difficult to reach by commercial lasers. In this study, we investigate a generation of coherent blue light (CBL) via four-wave mixing (FWM)-based up-conversion processes in cesium (Cs) vapor. A bichromatic pumping scheme with 852-and 917-nm lasers drives the Cs atoms to the 6D5/2 excited level, followed by cascaded decay of 6D(5/2) -> 7 (P)(3/2) -> 6 S-1/2, producing 456-nm CBL under phase matching conditions. The fluorescence in multiple bands from blue to near-and far-infrared in the FWM process is demon-strated under different experimental conditions. To optimize the experi-mental parameters, we investigate the dependence of 456-nm CBL on the vapor temperature, frequency, and intensity of the two pump lasers. A maximum power of 2.94 mW is achieved with pump powers of 430 mW (for 852 nm) and 47(0) mW (for 917 nm). The corresponding conversion effi-ciency is 1.5%/W, three-fold higher than those in previous studies. Our results can contribute to fundamental research on atom-photon interac-tions and quantum metrology.

Automated summary

In this study, coherent blue light (CBL) was generated via four-wave mixing (FWM)-based up-conversion processes in cesium vapor. By adjusting experimental parameters, a maximum power of 2.94 mW of CBL at 456 nm was achieved with a conversion efficiency of 1.5% per watt, which is three times higher than previous studies. These results contribute to fundamental research on atom-photon interactions and quantum metrology.