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0BBO crystals for nonlinear- and electro-optics applications
A. Kokh*, D. Kokh, E. Simonova, O. Safonova
Sobolev Institute of geology and mineralogy, 630090, Novosibirsk, Koptyug ave., 3
* a.e.kokh@gmail.com
Over a period of approximately three decades, the technology of beta barium borate (P-BaB2O4 or BBO) has been developed at the Institute of Geology and Mineralogy SB RAS [1-3]. The melt-solution method, also known as TSSG, is employed to facilitate the growth of noncentrosymmetric low-temperature P-phase. The use of oxides and fluorides of alkali metals as solvents represents a pivotal aspect of this process. The crucible containing the melt solution is surrounded by a thermal field with a third-order symmetry axis. This configuration gives rise to the formation of three convection cells within the melt solution, which enhances the mixing speed and yield coefficient. The improved flow in the vicinity of the crystallisation front postpones the effect of concentrational supercooling, thereby enhancing the optical quality. The photographs illustrate the BBO crystal, with a weight of 422 grams, that was grown in a 100 mm diameter crucible. The crystal can be used to produce non-linear optical elements with various orientations up to 10^15^18 mm and electro-optical modulators up to 8x8x20 mm with 1:1000 contrast.
Fig. 1. BBO crystal weighted 422g, top and side views.
[1] A.E. Kokh, T.B. Bekker, V.A. Vlezko, K.A. Kokh, Development of the technique of p-BaB2O4 crystal growth in the heat field of threefold axis symmetry, J. Crystal Growth, vol. 318, No. 1, pp. 602-605, (2011).
[2] L. Deyra, A. Maillard, R. Maillard, D. Sangla, F. Salin, F. Balembois, A.E. Kokh, P. Georges, Impact of BaB2O4 growth method on frequency conversion to the deep ultra-violet, Solid State Sciences, vol. 50, pp. 97-100, (2015).
[3] E. Simonova, A. Kokh, V. Shevchenko, A. Kuznetsov, A. Kragzhda, P. Fedorov, Growth of p-BaB2O4 Crystals from Solution in LiF-NaF Melt and Study of Phase Equilibria, Crystal Research & Technology, vol. 54, 1800267 (8 pgs), (2019).
Work is done on state assignment of IGM SB RAS (122041400031-2)
