Spectroscopy of V4+ and V3+ ions in a forsterite crystal

The absorption spectra of impurity vanadium ions in forsterite crystals are studied in the wavelength range from 600 to 2000 nm, It is found that the V4+ ion in the tetrahedral coordination in crystals grown by the Czochralsk i technique exhibits strong absorption in the range from 600 to 1200 nm, Th e intense electron-vibrational progressions in the absorption spectra of im purity d-ions in crystals were observed for the first time at temperatures 300 and 77 K In the authors' opinion, these progressions appear due to the formation of the oxovanadate complex and distortions of the structural tetr ahedron, The forsterite crystal doped with V4+ ions has a very high absorpt ion cross section (up to 2.1x10(-18) cm(2)) and a continuous broad absorpti on band, which makes this crystal promising as a passive laser switch in th e range between 600 and 1200 nm, At the same time, the V4+ ions in the fors terite crystal do not emit luminescence because of a high probability of th e nonradiative relaxation of their excited state. It is shown that luminesc ence of a V:Mg2SiO4 crystal is related to the tetrahedral V3+ ion.