Raman scattering and Nd3+ laser operation in NaLa(WO4)2

The continuous-wave laser operation of Nd-doped tetragonal NaLa(WO4)(2) crystal is studied at room temperature by optical pumping in the spectral region overlapping AlGaAs diode laser emission. This crystal has inhomogenously broadened optical bands. From the room-temperature spectroscopic parameters determined it is found that the optimum Nd concentration for the F-4(3/2) -> I-4(J) laser channels must be in the 3-5 at.% range. For J = 11/2 and 13/2 channels (lambda approximate to 1.06 and 1.3 mu m) the most favourable polarization configuration is parallel to the crystallographic c axis, while for J = 9/2 little polarization dependence of the laser efficiency is predicted. Laser operation was achieved with a 3.35 at.% Nd-doped sample grown by the Czochralski method. The laser operation was tested in an hemispherical optical cavity pumped by a Ti:sapphire laser. Stimulated emission at lambda = 1056 nm was achieved for a wide spectral pumping range, lambda = 790-820 nm. Stimulated Raman scattering was achieved in the picosecond regime with an efficiency similar to that of monoclinic KY(WO4)(2) reference compound.