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Topological Kondo insulators have been attracting great attention from the condensed-matter physics community due to their fascinating topological and strongly correlated properties. Here, we report angle-dependent c-axis magnetoresistance (MR) oscillations in a Kondo insulator, SmB6 single crystal, in a magnetic field of up to 13 T rotated in the ab-plane. Four-fold symmetric MR oscillations are first observed above 8 K, which result from the four-fold (C4) degeneracy of the bulk Fermi surface of SmB6. With decreasing temperature down to 2.3 K, the C4 symmetry of the MR oscillations gradually weakens and C2 symmetry appears. This demonstrates a crossover from three-dimensional bulk states to two-dimensional surface states and implies the possible emergence of topological nematic states. Our experimental observations shed new light on the metallic surface states and nematic states in the Kondo insulator SmB6. [ABSTRACT FROM AUTHOR]

A series of K(DxH1−x)2PO4 (DKDP; x = 0, 12, 70, and 80%) crystals were grown using the point-seed technique. A positive nonlinear refractive index is exhibited, implying a self-focusing effect. The nonlinear refraction along the z-direction is greater than that along the II-direction, indicating that the distribution of the H2PO4− and D2PO4− groups have a critical influence on the nonlinear refraction. The nonlinear refraction effect of “point-seed” crystals is greater than that of traditional growth crystals, demonstrating that the crystalline quality is a major factor. Compared to the pyramid region, the prism region has a larger nonlinear refraction effect. The vital parameters n2 and have been calculated and the results allow for DKDP applications. [ABSTRACT FROM AUTHOR]

Large Ba2TiSi2O8 crystals were successfully grown by the Czochralski technique. The stimulated Raman scattering properties of the Ba2TiSi2O8 crystals were investigated for the first time, and the first (558 nm) and second (587 nm) Stokes lines were generated in an ultracavity single-pass configuration excited by 532 nm picosecond pulses. The output energy and conversion efficiency of the scattering process as functions of pump energy were studied, and the highest conversion efficiency was found to be 31.8%. The experiments indicate that Ba2TiSi2O8 is a novel active crystal suitable for solid-state Raman laser applications. [ABSTRACT FROM AUTHOR]

KDP crystals were grown by the "point seed" rapid growth technique from aqueous solutions with different organic additives, including NTA, HEDTA, EDTA and DCTA. The growth rates were up to about 20 mm/day. The influences of these organic additives on the growth habit and optical properties of these as-grown KDP crystals have been studied. Such organic additives were all found to be able to enhance the solution stability and promote the growth rate for the (100) face of KDP crystals. Furthermore, the UV transmittance and laser damage threshold of the KDP crystals were both increased with the addition of these organic additives. It is proposed that the beneficial influences are due to the chelating action of such organic additives with metal ion impurities in the growth solutions. [ABSTRACT FROM AUTHOR]