Diode-pumped continuous wave and passively Q-switched Tm,Ho:LLF laser at 2 µm.

A compact diode-pumped continuous wave and passively Q-switched Tm,Ho:LuLiF(4) laser is demonstrated. The maximal output power of 381 mW at 2069 nm in continuous wave regime is obtained at an absorbed pump power of 1.5 W. By using a Cr(2+):ZnS saturable absorber, the maximum Q-switched average output power of 74 mW is obtained at 2055 nm. The pulse width and pulse energy are almost independent of the absorbed pump power, with the maximal values of 1.2 μs and of 13 μJ respectively. The pulse repetition frequency can be tuned almost linearly from 1 to 5.8 kHz by changing the absorbed pump power. Furthermore, a comparative analysis of laser performances with different output couplers is first carried out.