YVO4 crystals – puzzles and challenges

Work on optical properties of undoped and rare-earth doped YVO 4 crystals is briefly reviewed. Fundamental spectroscopic parameters relevant to laser performance of YVO 4 containing erbium, thulium and holmium, derived from absorption and emission spectra and from excited state relaxation dynamics, have been presented. Laser performance of YVO 4 :Er has been reported and laser potential of YVO 4 doped with thulium and holmium has been assessed. Anomalous phenomenon of up-conversion of IR radiation into red emission in YVO 4 :Yb,Ho and puzzling anti Stokes emission in nominally undoped YVO 4 have been discussed.