Passively Q-switched mode-locked Ho,Pr:LiLuF4 laser operating at 2.9 µm with semiconductor saturable absorber mirror

We demonstrated a passively Q-switched mode-locked 2.9 µm Ho,Pr:LiLuF4 bulk laser based on a semiconductor saturable absorber mirror for the first time, to the best of our knowledge. A stable pulse train with a modulation depth of nearly 100% was obtained. The mode-locked pulse width inside the Q-switched pulse envelope was estimated to be approximately 800 ps with a repetition rate of 47.27 MHz. The maximum average output power was determined to be 146 mW with a Q-switched pulse repetition rate of 18.2 kHz at a center wavelength of 2883 nm.