Shekhvotsov O. Tecnologies of borate, vanadate, tungstate and molybdate single crystal production for active elements of lasers operating at 1,06 and 1,5 m

The new crystal growth technology of binary borate Ca3RE2(BO3)4 (RE = Y, Gd) has been developed. The technology is based on solid state synthesis at 110-140°С, 210-230°С, 450-500°С, 730-750°С for 10-12 hours for every temperature interval. These conditions supply synthesis of stoichiometric charge. The growth of pure and Nd, Yb, Er – doped crystals free of impurity phases by the Czochralski method with the use of Pt or Ir crusibles and crystallization up to 70% melt has been demonstrated. Full substitution of rare earth cations (Y or Gd) by Nd has been done and new Ca3Nd2(BO3)4 single crystal has been grown for the first time. Its crystal structure was identified. Laser operation at 1.06 m for the active element of Ca3Y2(BO3)4:Nd crystal under flash lamp pumping in free running mode has been demonstrated for the first time. Parameters of laser operation for the active element of Ca3Gd2(BO3)4:Nd crystal were better than published erlier and obtained under the same conditions. New active elements of Ca3RE2(BO3)4:Yb,Er (RE = Y, Gd) single crystals for 1.53 m lasers have been produced. The working model of laser operating at 1.53 m under diode pumping has been developed together with Belarusian National Technical University. The parameters of working model of laser: wavelength - 1.53 m, slope efficiency – 13%, output power – up to 0.5 W, contnious wave operation. The crystal growth technology of binary vanadates free of scattering centers has been developed. Laser operation at 1.06 m for the active elements of Сa9La(VO4)7:Nd and Ca10Li(VO4)7:Nd crystals under flash lamp pumping in free running mode with slope efficiencies of 0.99% and 0.87%, respectively has been demonstrated for the first time. New single crystals Сa9Nd(VO4)7, Ca10M(VO4)7 (М - Li, Na, K) and Ca10.5-xPbx(VO4)7 (х=1.8; 3.5; 4.9) with non-symmetrical crystal structure have been grown for the first time. These crystals extend the range of non-linear optic materials. The R cR3c phase trasition was not observed for Ca9Y(VO4)3(PO4)4 crystal. High temperature structure modification R c has been obtained at room temperature and its unit sell parameters have been studied. The lead tungstate molybdate solid solution, SrWO4 and CaMoO4 crystals have been grown. Raman spectra of the crystals have been studied and peaks identified. For PbW0,5Mo0,5O4, SrWO4 and CaMoO4 crystals 1nd, 2nd and 3rd Stokes have been observed.