V:YAG saturable absorber for flash-lamp and diode-pumped solid state lasers

V:YAG saturable absorber was used for efficient Q-switching and mode-locking of Nd:YAG and Nd:YAP flash-lamp or diode pumped lasers operating in 1.3 mm region. Crystals of Yttrium-Aluminum Garnet (YAG) doped with three-valence vanadium V³⁺ in tetrahedral position (V:YAG) were grown using of Czochralski method in reducing protective atmosphere. High purity oxides were used for crystal growth (Y₂O₃ (5N), Al₂O₃ (5N), V₂O₅ (4N)). Concentration of V₂O₅ in the melt reached up to 1 wt. %. Discs of the diameter 5 or 10 mm and of various thickness were machined from grown V:YAG crystals. The discs were both sides polished and AR coated so that minimum reflectivity at 1.08 and 1.34 microns was reached. The initial transmission of the saturable absorber was dependent on the sample's thickness and its annealing process. We report stability improvement of passively mode-locked (by these V:YAG crystals) Nd:YAP flash-lamp pumped lasers. The maximum output energy 53 mJ at wavelength 1340 nm was obtained for Nd:YAP flash-lamp pumped laser operating at repetition rate 5 Hz. Mode-locked train envelope width was measured to be 22 ns (FWHM). Individual pulses inside the train were shorter than 1 ns. Also results with composite Nd:YAG rod Q-switched by V:YAG crystal and with Nd:YAG/V:YAG monolith rod under CW longitudinal diode pumping was obtained and compared. These laser systems represent new powerfull sources in the near infrared region.