Theoretical analysis on improving output power of continuous-wave single-wavelength two-photon pumped Rb-vapor laser with mid-infrared seed laser

We theoretically prove that introducing 5.23-mu m mid-infrared (MIR) seed laser can greatly increase output power of two-photon pumped Rb-vapor laser (Rb-TPAL) for the first time. Firstly, MIR laser stimulated radiation is added to the three-dimensional calculation model we reported in Ref. [1]. Then we simulate the Rb-TPAL pumped by a high-power continuous-wave laser diode and analyze the effects of MIR seed power and direction, vapor cell temperature and length, waist radii of pump and MIR seed, and output mirror reflectance on the output characteristics. The results show that by optimizing the above parameters, the MIR seed laser can not only significantly improve the output power and conversion efficiency of blue and MIR laser, but also reduce the pump and temperature thresholds of blue laser. This study can be useful for designing a TPAL system with high-power dual-waveband laser output.