The wavelength tunability of a diode-pumped laser, based on Yb 3+ -doped mixed garnet Gd 3 Ga 5−x Al x O 12 (Yb:GGAG, x ≈ 2.2, 4.25% Yb/Gd, 2.7 mm thick) crystal was investigated. Absorption and emission spectra together with fluorescence decay time were measured. The longitudinally diode-pumped Yb:GGAG laser was continuously tuned over ∼47 nm (from 1019 nm up to 1066 nm). The maximum output power amplitude of 1.6 W was obtained at wavelength 1042 nm with an absorbed pump power amplitude 6.9 W. The corresponding tunable laser slope efficiency was 30%.

Laser-induced damage experiments on HfO2 and Nb 2 O 5 thin films were performed with 500 fs pulse duration at 1030 nm wavelength. Threshold fluences as a function of beam size have been determined for effective beam diameters ranging from 40 to 220 µm, in single shot regime. The results suggest no beam size effect related to material properties in the investigated range, but size effects related to the metrology. The results indicate the importance of appropriate focusing conditions and beam measurement to qualify the optics for use in lasers with large beam sizes.

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