Compact dual-crystal Tm,Ho:YLF laser with balanced orthogonal polarization output power.

The compact dual-crystal orthogonally polarized Tm,Ho:YLF laser with balanced orthogonal polarization output power was reported for the first time, to the best of our knowledge. Two pieces of a-cut Tm,Ho:YLF crystals were placed compactly with their c-axis perpendicular. The maximum multimode total output power of 460 mW was obtained with the slope efficiency of 28.2%, and the M factor value was measured to be 1.07. By adjusting the pump focus position along the optical axis in the process of changing pump power, the balanced output powers in the two orthogonal polarization directions were successfully achieved, and the maximum output powers of the P-polarization and S-polarization states were both 215 mW. Inserting two uncoated solid state etalons into the resonator, the dual-wavelength single-longitudinal-mode laser with orthogonal polarization was obtained. The output powers at P-polarized 2052.1 nm and S-polarized2065 nm were 71mW and 62mW, respectively, and the M factor was 1.26. The orthogonally polarized dual-wavelength laser at 2 µm can be used as a seed laser for differential absorption lidars and coherent THz wave generation.