Lebedenko O. Origin of activator centers in RE2SiО5:Pr3+ (RE=Y, Gd, Lu) and Al2O3:Ti3+

Object - crystals of Y2SiO5, Lu2SiO5 and Gd2SiO5 oxyorthosilicates doped by Pr3+ and Al2O3 crystals doped by Ti3+ ions; aim - to ascertain the microscopic origin of impurity centers in RE2SiO5:Pr3+ (RE=Y, Gd, Lu) and Al2O3:Ti3+ crystals and to study physical regularities of formation of energy spectra of electron excitation and relaxation channels of the excitation energy in the wide 1,5-300 K temperature range; methods - selective laser spectroscopy; time-resolved spectroscopy; time-correlated single photon counting; results, novelty - Structural features of Pr3+ energy spectrum in the RE2SiO5:Pr3+ (RE=Y, Gd, Lu) crystals have been studied in the wide 1,5-300 K temperature range at concentration of the activator ions of 0,3-1,8 at. %. Quasi-symmetry of nonequivalent cation sites and the absence of the interaction between nonequivalent optical centers in a Y2SiO5:Pr3+ crystal have been found. The coefficients of electronic excitation diffusion and transfer parameters have been determined. The influenceof defect composition of the crystal lattices on parameters of electron-phonon interaction of doped ions and activation energy of nonradiative loses in a Al2O3:Ti3+ crystal have been revealed; field of implementation - laser spectroscopy; development of new optical materials and active laser medium