Passively Q-switched Yb:LuPO₄ laser based on a coupled cavity with few-layer WSe₂ acting as saturable absorber

We report on a passively Q-switched coupled-cavity Yb:LuPO₄ laser oscillating at 1005–1020 nm with a sapphire based few-layer WSe₂ serving as saturable absorber. With 12.2 W of pump power absorbed, an average output power of 3.32 W is produced at a repetition rate of 1.34 MHz with a slope efficiency of 38%; the resulting pulse energy, duration, and peak power are respectively 2.5 µJ, 28 ns, and 89.3 W. These results demonstrate the great potential of few-layer WSe₂ for use as saturable absorber in developing multi-watt, high-repetition-rate, nanosecond passively Q-switched solid-state lasers in the 1 µm spectral region. (letter)