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We report on short pulse generation from a passively Q-switched Pr3+:LiYF4 laser operating at 640 nm. By reducing the cavity length and utilizing Co:MgAl2O4 as the saturable absorber, we obtain the shortest pulse durations from any Q-switched Pr3+ laser. Under pumping with a frequency-doubled optically pumped semiconductor laser at a wavelength of 479.05 nm we realized (8.5 ± 1) ns long pulses at a repetition rate of 0.78 MHz from a 7.5 mm long cavity at an average output power of 1.0 W. In that case, the laser pulse energy and duration were 1.3 µJ and 8.5 ns, respectively. The highest pulse energy amounts to 1.8 µJ at a pulse peak power of 0.19 kW in 9.2 ns pulses at a repetition rate of 0.48 MHz.

We report on few-ns pulses with kW peak power in the red and orange spectral range obtained from a passively Q-switched Pr3+:YLF laser. A compact resonator and thorough investigation of the Co:MgAl2O4 saturable absorber initial transmission enables peak powers in excess of 1.1 kW at pulse durations of 2.4 ns and 5.3 ns at 640 nm and 607 nm, respectively. These are the shortest pulse durations among any Q-switched Pr3+ laser and make this system a suitable front end for efficient frequency doubling into the UV range.

In this work, we present the visible laser performance of improved optical quality Czochralski-grown 4 at.% Pr3+-doped Sr0.7La0.3Mg0.3Al11.7O19 (Pr:ASL) single crystals in the deep red (726 nm), the red (645 nm) and the orange (620 nm) range using two different pumping sources. Using a high beam quality frequency doubled Ti:sapphire laser with 1 W output power as pump source, deep red laser emission was reached at a wavelength of 726 nm with 40 mW of output power and a laser threshold of 86 mW. The corresponding slope efficiency was 9%. At 645 nm in the red, up to 41 mW of laser output power were obtained with 15% slope efficiency. Moreover, orange laser emission at 620 nm was demonstrated with 5 mW output power and 4.4% slope efficiency. Using a 10 W multi-diode module as pumping source allowed to obtain the highest output power of a red and deep-red diode-pumped Pr:ASL laser to date. The respective output powers at 726 and 645 nm reached 206 mW and 90 mW.

We investigate the dependence of the visible laser performance of Tb3+:LiLuF3 (Tb:LLF) on the ultraviolet (UV) pumping wavelength and present the first, to the best of our knowledge, UV-laser-diode-pumped Tb3+-based laser. We find an onset of thermal effects already at moderate pump power for UV pump wavelengths with strong excited-state absorption (ESA), which vanishes at pump wavelengths with weak ESA. Pumping with a UV laser diode emitting at 378.5 nm enables continuous wave laser operation in a 3-mm short Tb3+(28 at.%):LLF crystal. Slope efficiencies of 36% at 542/544 nm and 17% at 587 nm are obtained with a minimum laser threshold as low as 4 mW.