Near infrared rubidium 62P3/2,1/2→62S1/2 laser

An optically pumped near infrared rubidium (Rb) pulsed, mirrorless laser has been demonstrated in a heat pipe along both the 62P3/2-62S1/2 transition at 2.73 µm and the 62P1/2-62S1/2 transition at 2.79 µm. The bleached limit, slope efficiency, and maximum laser output energy of the near infrared Rb laser scale linearly with increasing Rb density, contrary to prior results. Previously, a maximum output energy of ~5 nJ had been observed before a rollover occurred in the scaling of output energy with rubidium concentration. In this experiment, the maximum laser output energy observed was ~100 nJ, with no indication of any scaling limitation. A maximum slope efficiency of 1.7×10−4 was observed. A small percentage of the pump photons were absorbed even at the maximum Rb density attainable in the heat pipe, indicating that laser efficiency could be scaled to near the quantum efficiency. Additionally, the hyperfine structure and absorption spectral profile of the 52S1/2-62P1/2 and 52S1/2-62P3/2 (blue) pump transitions were studied using a cw pump source.