Growth and non-linear optical properties of lithium triborate crystals

摘要

The Li_2O-B_2_2O_3-MoO_3 ternary system was investigated to determine the region of growth of lithium triborate Li_2O.3B_2O_3 (LBO) crysals with good optical properties. The top-seeded solution growth method, the method kof spontaneous crystallisation and solid-state reactions were used in this investigtion. The phase were defined by the method of X-ray power diffraction. The data obtained in these experiments mde it possible to choose the region of compositions of solutions in the Li_2O-B_2_2O_3-MoO_3 systems for the successful grwth of LBO signle crystals. LBO signle crystals, up to 100×82×45 mm~3 in size nd 290 g in weight, were grown free of cracks, bubbles and inclusions. These signle crystals were of high opticla qualtiy: wavefront distortion (fringe per mm for λ=0.633 μm) was lower than 1:150 absorption losses (0.25 μm<λ<2.5μm) in the resultant LBO signle crystals were lower than 0.005 cm~-1, and the damge threshold at λ=1.06 μm, τ=10 ns in the LBO single crystals was more than 10.0 GW/cm~2. High performance non-linear optical elemens of various optical orientations, up to 20×20×20 mm~3 ion size, were fabricated on our LBO crystals.