Dual-band switched unidirectional Ho:YLF ring laser with wavelength tunability

Tunable single-longitudinal-mode (SLM) ring Ho:YLF laser with intra-cavity isolator is investigated for 2.05 µm and 2.06 µm band based on single resonator, which is realized dual-band SLM laser conversion by a polarizer. Up to 548 mW SLM power with beam quality factor M² of 1.1 is achieved at wavelength of 2064.63 nm, and the corresponding slope efficiency is 26.7%. Wavelength tuning ranges from 2063.91 nm to 2065.71 nm and 2050.65nm to 2053.15nm can be demonstrated. The highest SLM power around P12 and R30 CO₂ absorption peak of 2064.41 nm and 2050.96 nm are 540 mW and 500 mW, respectively. The power instability within 30 minutes is around 0.14%. As we know, dual-band switched Ho:YLF laser operation at SLM with wavelength tunability is reported for the first time for the potential application of CO₂ differential absorption lidar.