Observation of laser oscillation from CaGa2S4:Eu2+

The first observation of laser oscillation from a single crystal of CaGa2S4 . Eu2+ (1 at%) is described in this report. A liquid nitrogen cooled thin platelet (0.8 mm thick), whose one flat surface was coated with aluminum to increase the reflectivity, was excited from the other uncoated side with a pulsed dye laser beam having a photon energy of around 2.48 eV. When the input power density exceeded a threshold value of similar to 10MW/cm(2), a directional beam having a sharp spectral line at around 2.19 eV emerged from the sample. This laser was found to have interesting wavelength tunability extending to similar to 200 Angstrom, possibly related to the broad gain spectrum of Eu2+ emission in this material.