Continuous-wave and Q-switched Tm-doped KY(WO4)2 planar waveguide laser at 1.84 µm

High-quality monoclinic planar waveguide crystals of Tm-doped KY(WO4)2 codoped with Gd3+ and Lu3+ were grown by liquid-phase epitaxy. For the first time, planar waveguide lasing was demonstrated in a monolithic cavity in the 2 µm spectral range. The laser was operated in the Q-switched mode using a Cr2+:ZnSe crystal as saturable absorber and in the continuous-wave regimes. The Q-switched planar waveguide laser delivered pulse energies up to 120 nJ at a repetition rate of 7 kHz.