Experimental Study on a Passively Q-Switched Ho:YLF Laser with Polycrystalline Cr²⁺:ZnS as a Saturable Absorber

Output performance of a continuous-wave Tm:YAP laser pumped passively Q-switched Ho:YLF laser is demonstrated with a polycrystalline Cr²⁺:ZnS as the saturable absorber. We compare the experimental results at the three different distances L of the polycrystalline Cr²⁺:ZnS saturable absorber to the output coupler. The pulse width almost remains constant for different L, when the incident pump power is changed in the range of 7.9–27.1 W. The shortest pulse duration of 33.3 ns for L=105 mm and the highest average output power of 6.8 W for L=5 mm are obtained at the incident pump power of 27.1 W. The output wavelength of the passively Q-switched laser shifts to 2045.2 nm from 2064.7 nm in the cw operation. The beam quality factor of M² is 1.2.