High-power passively Q-switched Nd:KGW laser pumped at 877 nm

In this work, we demonstrate, for the first time, a high-power passively Q-switched N-g-cut Nd3+:KGd(WO4)(2)/Cr4+:YAG laser pumped at 877 nm. The maximum average output power of similar to 1.6 W is obtained at the pump power of 5.22 W, when a saturable absorber with 98 % of initial transmission is used. The corresponding pulse energy is up to 16 mu J. The maximum pulse energy of 25.3 mu J is achieved at a repetition rate of 59 kHz, by employing a saturable absorber with 95 % of initial transmission. The corresponding pulse width and average output power are 89.0 ns and 1.5 W, respectively. A careful cavity design and a good thermal management ensure nearly TEM00 output with M-2 <= 1.22 within the whole range of operation in both N-p and N-m directions at 877 nm pump.