Performance of a low-loss pulsed-laser-deposited Nd:Gd_3Ga_5O_12 waveguide laser at 106 and 094 µm

We report the laser performance of a low-propagation-loss neodymium-doped Gd₃Ga₅O₁₂ (Nd:GGG) waveguide fabricated by pulsed-laser deposition. An 8-$\mathit{\mu }\mathrm{m}$-thick crystalline Nd:GGG film grown upon an undoped Y₃Al₅O₁₂ substrate lases at 1.060 and 1.062 $\mathit{\mu }\mathrm{m}$ when pumped by a Ti:sapphire laser operating at 740 or 808 nm. Using a 2.2% output coupler, we observed a 1060-nm laser threshold of 4 mW and a slope efficiency of 20%. Laser action was also achieved, for what we believe is the first time in Nd:GGG, on the quasi-three-level 937-nm transition. With a 2% output coupler at this wavelength a laser threshold of 17 mW and a 20% slope efficiency were obtained. This demonstration of low propagation loss combined with the fact that these waveguides have a very high numerical aperture (0.75) makes pulsed-laser-deposited thin films attractive for high-power diode-pumped devices.