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Birefringence attracts increasing attention due to its extensive applications in the imaging spectrometer, laser devices and optical components. Stimulated by the discovery of the giant birefringence (GBF) in LaOBiS2 and AFBiS2, we explore its origin by checking three compounds with and without the BiS2 layer: Bi2OS2 (i.e., BiOBiS2), Bi2O2S and LaOAlS2. It is demonstrated that GBF appears only in the compounds with the BiS2 layer and is furthermore confirmed in MOBiS2 (M=Al, Ga, In and Sc) compounds. The result is useful for discovering/developing new-type birefringent crystal or even multifunctional materials. [ABSTRACT FROM AUTHOR]

LaOsSi3 single crystals are synthesized for the first time by an arc melting method. The crystal features a tetragonal BaNiSn3-type structure (space group I4mm) which lacks inversion symmetry along the crystallographic c axis and is isostructural with the intensively studied Rashba-type noncentrosymmetric superconductors LaRhSi3 and LaIrSi3. Unlike LaRhSi3 and LaIrSi3 displaying superconductivity, LaOsSi3 shows only metallic behavior over the measured temperature range of 2 K–300 K. The Sommerfeld coefficient γ derived from specific heat is 5.76 mJ·mol−1K−2, indicating that LaOsSi3 has a weak electronic correlation effect. The absence of superconductivity in LaOsSi3 may lie in the Os 5d bands in the electronic structure. If it is true, it would be useful to provide complementary knowledge in understanding the relation between conduction and the d bands of M in LaMSi3 compounds (M = transition metals). [ABSTRACT FROM AUTHOR]

Pr3+-doped calcium niobium gallium garnet (Pr:CNGG) single crystals with different Pr3+concentrations are successfully grown by the micro-pulling-down (μ-PD) method. The crystal structure, room-temperature absorption spectra, and fluorescence spectra of Pr:CNGG crystals are measured and discussed. The fluorescence results indicate their large dependence on the doping concentration. The fluorescence lifetime of the energy level is also determined. The results indicate that Pr:CNGG crystal could be a potential solid-state laser gain medium. [ABSTRACT FROM AUTHOR]