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Two samples of Er-Yb doped phosphate glass were tested as a gain medium of longitudinally diode pumped laser. One sample was a simple Er:Yb:glass rod (length 2.8 mm), second sample was composite rod consisting of 2.8mm long Er:Yb:glass and 6mm long YAG crystal. Diameter of both samples was 6 mm. Dopant concentration for Er:Yb:glass was 0.75 × 1020cm−3Er and 1.7 × 1021cm−3Yb. The goal of the experiment was to investigate an effect of the undoped YAG cap on the Er:Yb:glass laser operation. The active medium, fixed in cupreous heatsink, was placed inside the 150mm long resonator consisted of a flat pumping mirror (HR @ 1.52−1.65 m, HT @ 0.97 m) and curved output coupler (r = 150 mm, R = 97% @ 1.52−1.61 m). For Er:Yb:glass pumping a fiber coupled laser diode, operating in pulsed regime, was used. The pumping pulse width, energy, and wavelength were 1 ms, 10 mJ, and 975 nm, respectively. The decrease of Er:Yb:glass laser output pulse energy with increasing pumping repetition rate was observed for both samples. In case of simple Er:Yb:glass the energy dropped from 1.4mJ to 0.6mJ after pumping duty cycle increase from 0.5% to 6 %. In case of composite YAG/Er:Yb:glass active medium the relative output energy decrease was only 20% for pumping duty cycle increase from 0.5% to 10%. This result showed that the slope of the output energy decrease with increasing duty cycle was approximately four times slower for composite active media in comparison with simple Er:Yb:glass.

Influence of Ce3+-ions in Pr,Ce:YAlO3crystal on spectroscopic and laser characteristics has been investigated. Spectroscopic properties and preliminary laser results of GaN-diode pumped Pr,Ce:YAlO3active medium at room temperature have been reported and compared with the same crystal without Ce3+-ion. Co-doping of the active medium by Ce3+-ions was proposed for crystal property improvement in terms of color center formation caused by UV radiation.

Laser characteristics of Pr:YAlO3 microchip laser operating in the near-infrared spectral region are reported. For active medium pumping, GaN laser diode providing up to 1 W of output power at ~448 nm was employed. Microchip resonator was formed by dielectric mirrors directly deposited on the Pr:YAlO3 crystal surfaces. The continuous-wave output radiation at 747 nm with maximum power of 139 mW has been extracted from the microchip laser system. Slope efficiency related to the incident pumping power was 25%.

A compact diode pumped Q-switched lasers, operating at wavelength 1031 nm, were based on the composite crystal Yb:YAG/Cr:YAG. This composite crystal (diameter 3mm) consisted of diffusion bounded 3mm long Yb:YAG (10 at.% Yb/Y) and 1.6mm long Cr:YAG crystal (initial transmission 85% @ 1031 nm). External resonator allowing to tune generated Q-switched pulse parameters or microchip configuration offering the shortest pulses and highest peak power were tested for this device. For longitudinal pumping of Yb:YAG gain medium, fibre coupled (core diameter 200 m, NA= 0.22) laser diode, operating at wavelength 968 nm, was used. In the first case, Yb:YAG/Cr:YAG composite crystal was AR-coated and placed inside the 150mm long semihemispherical resonator consisted of a flat pumping mirror (HR @ 1.01 − 1.09 m, HT @ 0.97 m) and curved output coupler (r = 150mm) with reflectivity 70% @ 1031 nm. Generated pulses with the peak power 23 kW were 17 ns long (FWHM). The highest generated pulse energy was 0.38 mJ. In the second case, the resonator mirrors were deposited directly on the crystal faces. The output coupler reflectivity was 85% @ 1031 nm. In this compact microchip configuration, 140 ps long (FWHM) pulses with energy 0.13mJ and peak power 0.92MW were generated at wavelength 1031 nm.

The impact of the V:YAG saturable absorber nonlinear transmission polarization anisotropy on Q-switched laser system was investigated. Two various cuts ([111] and [100]) of V:YAG crystal with the same initial transmission 87% @ 1.3 m were used as a passive Q-switch for longitudinaly diode pumped linearly polarized Nd:YAP laser operating at 1342 nm. This laser consisted of 8.2mm long Nd:YAP crystal placed in 100mm long semihemisferical resonator. The flat mirror in vicinity of Nd:YAP crystal was transparent for pumping radiation at 805nm and highly reflecting at operating wavelength 1342 nm. The curved output coupler (radius of curvature 146mm) had reflectivity 92% @ 1342 nm. The laser was tested under pulsed pumping for the duty-cycle 9% and under CW pumping. The laser output parameters (mean output power, pulse width, repetition rate, energy, and peak power) were measured for absorber turning around longitudinal crystal axis. In this configuration for [111]-cut of V:YAG the pulse energy and pulse width (FWHM) varied from 27 up to 38 J and from 50 to 40 ns, respectively. This corresponds to peak power rise from 0.55 up to 0.95kW. In case of [100]-cut the proper orientation of V:YAG in respect to oscillating radiation polarization allowed to increase pulse energy from 37 to 60 J and peak power from 1.3 to 3 kW. Simultaneously, the pulse width decreased from 28 to 20 ns. The results showed that proper choice of saturable absorber cut and orientation can significantly improve giant pulse parameters.