An Actively Mode-Locked Ho:YAG Solid-Laser Pumped by a Tm-Doped Fiber Laser**Supported by the National Natural Science Foundation of China under Grant Nos 61308009 and 61405047, the China Postdoctoral Science Foundation Funded Project under Grant Nos 2013M540288 and 2015M570290, the Fundamental Research Funds for the Central Universities Grant under Grant Nos HIT.NSRIF.2014044 and HIT.NSRIF.2015042, the Science Fund for Outstanding Youths of

Abstract

An actively mode-locked Ho:YAG laser pumped by a diode-pumped Tm-doped fiber laser is reported. For the cw operation, we obtain the maximum output power of 3.43 W with a central wavelength 2022.2 nm at the maximum incident pump power of 11.4 W, corresponding to a slope efficiency of 34.5%. The beam quality factor M2 is 1.16, and the output beam is close to fundamental TEM00. In the case of the CWML operation, a stable pulse train is generated with an average output power up to 3.41 W with a slope efficiency of 34.3% at the incident pump power of 11.4 W and a pulse duration of 294 ps at a repetition rate of 81.92 MHz. In addition, the maximum single pulse energy is 41.6 nJ.