新型红外非线性光学晶体BaGa2GeSe6的生长与器件制备

钡镓锗硒(BaGa₂GeSe₆,BGGSe)晶体是由中国科学家发明的一种性能优异的新型红外非线性光学材料.目前国内未见到关于该晶体的大尺寸制备报道.本研究采用自制的双温区管式炉成功合成出BGGSe多晶,单次合成量达到400 g;采用坩埚下降法生长出大尺寸高质量BGGSe单晶,尺寸为φ30 mm×90 mm,为国内首次;通过定向、切割和抛光等处理工艺,成功制备出BGGSe晶体器件,为该晶体下一步的应用研究打下了坚实基础.     

新型可实用化红外非线性光学晶体研究进展

红外非线性光学晶体可以变频输出中远红外激光,在国防和民用方面都有重要应用.本文综述了近十年来发现的具有实用前景的新型红外非线性光学材料的研究进展,主要讨论已经获得较大尺寸单晶的新材料.这些晶体具有优秀的综合性能,包括足够大的非线性光学系数,宽的红外透过范围,合适的双折射,较好的单晶生长习性和稳定的物化性质.本文将从晶体结构、晶体生长、物化性能、红外激光输出等方面进行综述,并对红外非线性光学晶体未来的发展方向做出一定的讨论.     

BPO4晶体的生长及孪晶缺陷分析

利用助熔剂法,采用顶部籽晶技术生长出新型非线光学晶体材料BPO4（简称BPO）晶体,用同步辐射白光X射线形貌术拍摄了（001）,（101）切片的形貌像,观察到了生长孪晶结构,从形貌像中可明显地观察到游离于主晶形貌像之外的孪晶形貌像,并从结构上解释了孪晶的形成原因。     

Nd3+:CaLa2B10O19晶体的生长和性质研究

用泡生法生长出不同Nd3+掺杂浓度的Nd3+:CaLa2B10O19(NLCB)晶体,测试了晶体的透射光谱、荧光光谱、倍频效应等性质.NLCB晶体在580nm和805nm处有很强的吸收,能与二极管激光器有效耦合.在900nm和1.06μm处各有一荧光峰,1.06μm处的荧光寿命为75μs.NLCB的粉末倍频效应为KDP的2倍.     

Crystal growth,structural and physical properties of the 5d noncentrosymmetric LaOsSi_3

LaOsSi3 single crystals are synthesized for the first time by an arc melting method. The crystal features a tetrag- onal BaNiSn3-type structure （space group 14mm） which lacks inversion symmetry along the crystallographic c axis and is isostructural with the intensively studied Rashba-type noncentrosymmetric superconductors LaRhSi3 and LaIrSi3. Un- like LaRhSi3 and LaIrSi3 displaying superconductivity, LaOsSi3 shows only metallic behavior over the measured temper- ature range of 2 K-300 K. The Sommerfeld coefficient ]/derived from specific heat is 5.76 mJ.mol-1 -K-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）.     

Temperature tuning of BaGa4Se7 optical parametric oscillator

The temperature tuning of BaGa₄Se₇(BGSe)was demonstrated for the first time,to the best of our knowledge.When the temperature of BGSe(56.3°,0°)was raised from 30℃ to 140℃,the idler light under type Ⅰ raised from 3637 nm to 3989 nm,the tunable range reached 352 nm,and Δλ₂=ΔT reached 3.20 nm/℃.We calculated the phase matching curve of BGSe when Φ and T took different values.The relationship between θ and Δλ₂=ΔT was obtained by fixing Φ at 0°.The maximum Δλ₂=ΔT and its corresponding(θ,Φ)phase matching type were reported under different fixed λ₂(3μm,3.2μm,...,5μm).