OPTICAL PROPERTIES OF LiNbO<sub>3</sub>:B CRYSTALS
The optical properties of nominally pure LiNbO<sub>3stoich</sub>, near-stoichiometric LiNbO<sub>3stoich</sub> (6,0 wt% K<sub>2</sub>O), LiNbO<sub>3cong</sub> and LiNbO<sub>3</sub>:B(0,55 and 0,83 mol% B<sub>2</sub>O<sub>3</sub> in the charge) crystals in the visible region of the spectrum (λ = 380-700 nm) were studied by photoluminescence. LiNbO<sub>3</sub>:B crystals were grown by Czochralski using the technology of a direct solid-phase doping of the congruent charge by boron oxide (B<sub>2</sub>O<sub>3</sub>). The photoluminescence intensity increases in the series of crystals: LiNbO<sub>3stoich</sub>, LiNbO<sub>3stoich</sub> (6,0 wt% K<sub>2</sub>O), and LiNbO<sub>3cong</sub>. The photoluminescence intensity is determined by the concentration of deep electron traps (Nb<sub>Li</sub> - «niobium antisite») and the stoichiometry of these crystals. The photoluminescence intensity of LiNbO<sub>3</sub>:B (0,55 and 0,83 mol% B<sub>2</sub>O<sub>3</sub> in the charge) crystals is close to the photoluminescence intensity of LiNbO<sub>3stoich</sub> crystal. This can be explained by the fact that the composition and structure of LiNbO<sub>3</sub>:B (0,55 and 0,83 mol% B<sub>2</sub>O<sub>3</sub> in the charge) crystals approach the composition and structure of the stoichiometric crystal.