Compositionally tuned Nd:(Y_xLu_1-x)₃Ga ₅O₁₂-laser at 935 nm for H₂O-dial Systems

For future satellite based water vapor DIAL systems efficient and rugged sources preferably around 935 nm are required. Especially for the WALES system (Water Vapour Lidar Experiment in Space) four wavelengths between 935.561 nm and 935.906 nm (vac.) have to be addressed. A promising candidate for the direct generation within this spectral range is a simple diode pumped setup based on compositionally tuned neodymium-doped mixed garnet crystals. Within the scope of this work, novel Nd:(Y_xLu_1-x)3Ga₅O ₁₂-crystals (Nd:YLuGG) with different compositions (0≤x≤1) were investigated. Beside the characterization of some relevant crystal properties laser experiments in quasi-continuous operation, Qswitched operation and in single-longitudinal-mode operation were performed. By the R₂-Z ₅-transition wavelengths between 935.3 nm and 936.6 nm (vac.) can be addressed with different compositions x. At a repetition rate of 100 Hz nearly 6 mJ were extracted in longitudinal multimode around 935.7 nm (vac.) from a Nd:(Y_0.58Lu_0.42)₃Ga₅O ₁₂-crystal. The cavity was injection seeded and stabilized with the ramp-and-fire-method to obtain single frequency radiation. At 935.7 nm more than 4.7 mJ were generated. The laser could be tuned over a range of about ± 0.22 nm in singlelongitudinal- mode operation.