Growth and non-linear optical properties of lithium triborate crystals

The Li2O-B2O3-MoO3 ternary system was investigated to determine the region of growth of lithium triborate Li2O . 3B(2)O(3) (LBO) crystals with good optical properties. The top-seeded solution growth method, the method of spontaneous crystallisation and solid-state reactions were used in this investigation. The phases were defined by the method of X-ray power diffraction. The data obtained in these experiments made it possible to choose the region of compositions of solutions in the Li2O-B2O3-MoO3 system for the successful growth of LBO single crystals. LBO single crystals, up to 100 x 82 x 45 mm(3) in size and 290 g in weight, were grown free of cracks, bubbles and inclusions. These single crystals were of high optical quality: wavefront distortion (fringe per mm for lambda = 0.633 mu m) was lower than 1/150 absorption losses (0.25 mu m < lambda < 2.5 mu m) in the resultant LBO single crystals were lower than 0.005 cm(-1), and the damage threshold at lambda = 1.06 mu m, tau = 10 ns in the LBO single crystals was more than 10.0 GW/cm(2). High performance non-linear optical elements of various optical orientations, up to 20 x 20 x 20 mm3 in size, were fabricated on our LBO crystals. (C) 1999 Elsevier Science B.V. All rights reserved.