YVO4 crystals - puzzles and challenges

Work on optical properties of undoped and rare-earth doped YVO4 crystals is briefly reviewed. Fundamental spectroscopic parameters relevant to laser performance of YVO4 containing erbium, thulium and holmium, derived from absorption and emission spectra and from excited state relaxation dynamics, have been presented. Laser performance of YVO4 :Er has been reported and laser potential of YVO4 doped with thulium and holmium has been assessed. Anomalous phenomenon of up-conversion of IR radiation into red emission in YVO4:Yb,Ho and puzzling anti Stokes emission in nominally undoped YVO4 have been discussed.