544-nm Tb³⁺-doped LiYF₄ laser pumped by 488-nm InGaN laser diodes and high peak power operation with cavity-dumped <i>Q</i>-switching

We report a 544-nm <i>T</i> <i>b</i> ³⁺-doped <i>L</i> <i>i</i> <i>Y</i> <i>F</i> ₄ (Tb:YLF) laser pumped by two ∼488-<i>n</i> <i>m</i>, 2-W InGaN laser diodes in continuous-wave (CW) and cavity-dumped <i>Q</i>-switch operations. We obtained a CW output power of 482 mW with a slope efficiency of 43%. Cavity-dumped <i>Q</i>-switching generated 6-ns pulses with a pulse energy of 40 µJ at a repetition frequency of 100 Hz, resulting in the highest peak power of 6.7 kW ever reported for <i>T</i> <i>b</i> ³⁺-based lasers, to our knowledge. We analytically examined the influence of excited-state absorption and energy transfer upconversion on the small-signal gain of a Tb:YLF laser and concluded that their influence was negligible under our operating conditions.