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A highly efficient Tm:YLF-Ho:YAG laser system is presented in this paper. To obtain the narrow linewidth 1908 nm laser output, a volume Bragg grating combined with a Fabry-Perot (FP) etalon were used as wavelength selection devices. The maximum output power of 28.7 W was obtained with a slope efficiency of 42.3% in the Tm:YLF laser. An output wavelength of 1908.1 nm and FWHM linewidth of 60 pm were achieved at the maximum output level. Using this Tm:YLF laser as the pump source, high efficiency continuous wave and Q-switched operation of a Ho:YAG laser was demonstrated. Operating at continuous wave mode, up to 73.3% slope efficiency and 67.4% optical conversion efficiency were obtained in the Ho:YAG laser, corresponding to a diode-to-Ho optical conversion efficiency of 23.7%. For the Q-switched mode, when the incident Tm power was 27.3 W, the maximum single pulse energy of 3.4 mJ, pulse width of 15 ns and peak power of 229.3 kW were achieved at the pulse repetition rate of 5 kHz. The maximum average power of 18.3 W, pulse width of 18 ns and peak power of 103.6 kW were obtained at the pulse repetition rate of 10 kHz. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate an efficient cavity-dumped Ho:SSO laser linewidth-narrowed by a volume Bragg grating for the first time. When the incident pump power was 19.3 W, the maximum average output power of 6.33 W was achieved at a pulse repetition rate of 100 kHz, corresponding to the slope efficiency of 48.5% and optical conversion efficiency of 32.8%. The pulse width was kept at approximately 3.6 ns. The output wavelength was located at 2100.5 nm with a linewidth of 70 pm. In addition, the beam quality factor M2 of the cavity-dumped Ho:SSO laser at maximum output level was measured to be 1.5 by 90/10 knife-edge technology. [ABSTRACT FROM AUTHOR]