We report the first observation, to our knowledge, of three-level laser oscillator operation in a crystal activated with Mn5+. The material is Mn:Ba3(VO4)2 which exhibited laser oscillation at room temperature under pulsed 592 nm excitation. The laser emission occurs at 1181 nm with a threshold of 0.3 J/cm2. Spectroscopy indicates that this material operates as a three-level system on the 1E to 3A2 transition of the Mn5+ ion with tetrahedral coordination. The strong, broad absorption bands and 0.43 ms room-temperature lifetime make this system very promising for flash lamp AlxGa1−xAs diode pumping.

Laser action in chromium-doped forsterite (Cr:Mg2SiO4), pumped with a 1.064 μm Nd:YAG laser, was demonstrated for the first time. The free-running laser emission is centered at 1.221 μm and has a spectral width of 28 nm. An efficiency of 8% has been achieved with an uncoated crystal produced by the laser-heated-pedestal growth method. The available evidence suggests that the laser action is due to Cr4+ in tetrahedral sites.