五角棱镜的光束转向误差对波前测量的影响

从分析五角棱镜的角度制造误差产生的光学平行差入手，推导出确定入射光线和棱镜调整的表达式；利用棱镜转动定理建立了五角棱镜的光输出平面波前与其角度制造误差和导轨引起的运动误差之间的关系；并用计算机模拟试验分析了五角棱镜的角度制造误差和导轨引起的运动误差产生的扫描光束转向的波前误差。指出此研究结果有利于五角棱镜的加工和棱镜调整，还有利于大口径望远系统波前检测过程中扫描光束转向的波前误差的修正。     

Synthesis, Single-crystal Structure, and Optical and Magnetic Properties of CaEr2S4

Brown needle-like crystals of CaEr2S4 were isolated as the major product from a reaction of elements and binary sulfides by a two-step flux technique. CaEr2S4 crystallizes in the orthorhombic space group Pnma with a = 12.845(4), b = 3.862(4), c = 13.001(2) , V = 645.0(7) 3, Z = 4, F(000) = 880, μ(MoKα) = 27.794 mm-1, the final R = 0.0528 and wR = 0.0562 for 1070 observed reflections with I > 3σ(I). The CaEr2S4 structure forms a three-dimensional framework that consists of interconnected tetra-octahedral Er4S18 fragments. Ca2+ cations, in a monocapped trigonal prism geometry, are stuffed in two parallel rows into the one-dimensional channels along the b direction. CaEr2S4 is an infrared-transparent semiconductor with a band gap of 1.81 eV. Magnetic susceptibility measurements over 6～300 K indicate a Curie-Weiss paramagnetic behavior for the phase, with an effective magnetic moment of 9.64(1) μB per Er3+ ion.     

紫外超短脉冲激光放大过程中脉宽压缩的方案设计

采用放电泵浦KrF准分子激光放大器放大波长为248.4nm的紫外超短脉冲激光。对于能量为0.7mJ、脉宽为550fs的输入脉冲,在光束直径保持10mm不变的条件下,能量放大到15mJ,脉宽展宽到1200fs。为了压缩输出脉冲宽度,分析了群速度色散和自相位调制效应对脉宽展宽的影响。利用棱镜对,采用4种不同的实验方案对脉冲引入负的线性频率啁啾,以补偿KrF准分子激光放大器CaF2窗镜中的群速度色散和自相位调制对脉冲引入的正的线性频率啁啾。结果表明:在放大器之前放置棱镜对的方式可以在保持输出脉冲能量为15mJ的同时,在棱镜对间距为110cm的条件下,将输出脉冲宽度压缩到370fs,输出波长为248.4nm、带宽为0.4nm。     

Matlab-GUI在分光计测三棱镜的顶角及折射率实验的数据处理中的创新

在用分光计测三棱镜的顶角及折射率实验的数据处理过程中,用Matlab-GUI设计数据处理系统并编译成可执行文件,用此可执行文件处理实验数据,可以避免多次计算的繁琐,并且计算结果显示十分直观,使用方便,提高了我们大学生处理实验数据的能力,并且是大学物理实验数据处理方法的一种创新。     

基于角锥棱镜的非平面单频环形腔本征态分析

对基于角锥棱镜的非平面单频环行激光器的本征态问题进行了详细讨论,通过参考光线研究了该环形腔的光路闭合情况.腔内允许存在的四个本征椭圆偏振态,由于模式竞争,最终仅存一个本征模式振荡,从而实现单频运转.通过对腔内环路矩阵结构的分析,得出该环形腔中线偏振模式的产生需要系统的光路结构对称.对角锥棱镜的圆柱部分施加磁场,随着磁场的增大,对称光路结构中的本征态结构发生变化,并在适当磁场处出现线偏振模式.     

A semianalytical finite element method for stress and deformation analyses of bi-directional functionally graded truncated conical shells

Abstract

On the basis of Reissner’s mixed variational theorem, the authors develop a semianalytical finite annular prism method (FAPM) for three-dimensional (3D) stress and deformation analyses of bi-directional functionally graded (FG) truncated conical shells with various boundary conditions subjected to either uniformly or sinusoidally distributed loads. The material properties of the FG-truncated conical shell are assumed to obey a bi-directional power-law distribution of the volume fractions of the constituents through the meridian–thickness surface, the effective material properties of which are estimated using the rule of mixtures. Implementation of the current FAPMs shows their solutions converge rapidly and that the convergent solutions are in excellent agreement with the 3D solutions available in the literature.     

Preparation and Morphologies of AB6¯ Block‐Graft Copolymers

Microphase‐separated structures of a series of AB₆ block‐graft copolymers were studied by TEM and SAXS. Ten copolymers with the same polystyrene (S) backbone and six polyisoprene (I) grafts on the average but with different graft chain lengths were carefully synthesized by living anionic polymerization, covering the range 0.21 ≤ ?_S ≤ 0.90, where ?_S denotes polystyrene compositions. From TEM observation of the AB₆ block‐graft copolymers, it turns out to be clear that they show four microphase‐separated structures, S‐spheres, S‐cylinders(S‐prisms), alternative lamellae, and I‐cylinders. Among them, for example, the samples with 0.54 ≤ ?_S ≤ 0.58 shows prism structures whose cross sections of the S domains are close to hexagons, not circles, due to packing frustration of grafts. Composition dependence of morphologies of the present AB₆ block‐graft copolymers reveals their phase diagram is extremely asymmetric with respect to ?_S = 0.5. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 952–960     

新型棱镜产生近似无衍射线结构光

为了改善三角棱镜系统产生近似无衍射线结构光的能量均匀分布在若干条光斑上,不适合直接应用于三维表面测量且中心光斑对能量利用率较低的问题,提出了一种新型光学元件.该元件在三角棱镜的基础上,通过在其底部胶合一个与原三角棱镜底面大小相等,横截面为等腰梯形的凸台制成.采用几何光学的理论对新型光学元件的光束变换特性进行分析,结果表明其可以等效为两个不同底角三角棱镜的组合,平面光束通过新型光学元件后将产生中心光斑较强的近似无衍射线结构光.由衍射积分理论分析和模拟了新型光学元件后的空间光强分布特性.仿真的结果表明,衍射积分分析的结果与几何光学分析的结果是一致的:新型光学元件可以产生一种性能更好的近似无衍射线结构光.并且通过改变棱镜的结构参量,能够方便地调节光束的中心光斑尺寸、近似无衍射范围等参量.     

分析双Amici棱镜角度误差对色散的影响

双Amici棱镜为复合棱镜结构,作为成像光谱系统中的分光元件,避免了单棱镜色散结构存在的多种问题。双Amici棱镜的加工生产要对其各个角度提出生产指标,而角度误差对于光谱成像系统的色散性是有影响的。针对一种编码孔径成像光谱仪,设计了符合性能指标要求的双Amici棱镜,并从光线追迹的角度出发,计算得到双Amici棱镜色散的数学模型。针对给出的一特定光学系统中的棱镜结构推导了棱镜各个角度单独对线色散的影响,并分析给出各个角度构成的误差链对线色散的综合影响,最终给出了棱镜的生产指标。分析结果有助于指导系统中该棱镜的加工生产。     

变折射率组合三角棱镜产生无衍射线结构光

提出一种可产生大焦深无衍射线结构光的新型光学元件——变折射率组合三角棱镜,由正、负等腰三角棱镜胶合在一起设计而成,其变换光束特性与单个正等腰三角棱镜相同,等效折射率由正、负等腰三角棱镜折射率之差决定,因此可通过两个折射率接近的正、负等腰三角棱镜组合得到一个更加接近1的等效折射率,以获得更大焦深的无衍射线结构光,解决了单个正等腰三角棱镜小角度加工困难的技术问题。采用几何光学理论分析了产生无衍射线结构光的原理,计算了无衍射线结构光的相关参数。由衍射积分理论分析和模拟了新型光学元件后的光强分布特性。研究表明,平面波正面入射新型光学元件可以产生具有大焦深的无衍射线结构光。