Using the method of heat field symmetry control [5], large high quality LBO crystals of more than 1.3 kg have been grown. In accordance with the so-called Curie principle, rhombic LBO crystals were grown in the heat field of the same symmetry. Elements of excellent optical homogeneity with diameters up to 50 mm were used for frequency doubling of high energy 1053 nm laser beam. Second-harmonic energies up to 115 J [1] were produced and conversion efficiencies up to 90% were measured. (C) 2010 Elsevier B.V. All rights reserved.