Resonantly Fiber-Coupled Diode-Pumped Ho3+: YLiF4 Laser in Continuous-Wave and Q-Switched Operation

In this paper, the theoretical quantitative energy-level character and the experimental laser performance of resonantly fiber-coupled diode-pumped Ho
³⁺
: YLiF
₄
(Ho: YLF) laser are first presented. More precise 2.7-level character of diode-pumped Ho: YLF laser can be acquired with our theoretical analysis. With the experimental study, a maximum slope efficiency of 88.5%, corresponding to an output power of 1.85 W, was obtained. In actively Q-switched operation, a maximum pulse energy of 0.3 mJ was achieved at the repetition frequency of 5 kHz with a minimum pulse duration of 160 ns. At a maximum repetition frequency of 100 kHz, a pulse energy of 16 μJ was achieved with a pulse duration of 816 ns. Both the performance in continuous-wave and Q-switched regimes indicates that the current resonantly fiber-coupled diode-pumped Ho: YLF laser has great potential in certain conditions that require several watts of average output power.