High-speed scanning fiber-optic heterodyne interferometer using a micro-electro-mechanical system mirror and an f-theta lens

This paper describes a novel fiber-coupled heterodyne interferometer using a micro-electro-mechanical system (MEMS) mirror and an f-theta lens. In this interferometer system, the cross-polarized laser beams operating at 2 μm with the frequency difference of 100 kHz are introduced by means of the two acousto-optic modulators (AOM). The sample with diameter of 300 mm is uniformly scanned by the 1 mm laser beam with the help of the combined optical scanning configuration, a MEMS mirror and an f-theta lens. The output intermediate signal from the two channels, reference channel and the measurement channel, are processed in the 12 bit analog-to-digital (A/D) process system. Details of our interferometer scheme are discussed.     

高损伤阈值三倍频分离膜

 设计了Nd：YAG激光用三倍频分离膜,膜层材料为SiO₂和HfO₂。经过优化,膜系在355 nm处的反射率在99%以上,在532 nm和1 064 nm处透射率也在99%以上。采用电子束蒸发技术,在熔融石英基底上制备了样品,经测量,制备的分离膜光学性能与设计值接近。分离膜在355 nm激光辐照下的损伤阈值为5.1 J/cm²,并用微分干涉显微镜表征了薄膜损伤形貌。     

Approximate direct reduction method: infinite series reductions to the perturbed mKdV equation

The approximate direct reduction method is applied to the perturbed mKdV equation with weak fourth order dispersion and weak dissipation. The similarity reduction solutions of different orders conform to formal coherence, accounting for infinite series reduction solutions to the original equation and general formulas of similarity reduction equations. Painlevé II type equations, hyperbolic secant and Jacobi elliptic function solutions are obtained for zero-order similarity reduction equations. Higher order similarity reduction equations are linear variable coefficient ordinary differential equations.     

Plasmonic nano‐slits assisted polarization selective detour phase meta‐hologram

Traditional detour‐phase hologram is a powerful optical device for manipulating phase and amplitude of light, but it is usually not sensitive to the polarization of light. By introducing the light‐metasurface interaction mechanism to the traditional detour phase hologram, we design a novel plasmonic nano‐slits assisted polarization selective detour phase meta‐hologram, which has attractive advantages of polarization multiplexing ability, broadband response, and ultra‐compact size. The meta‐hologram relies on the dislocations of plasmonic slits to achieve arbitrary phase distributions, showing strong polarization selectivity to incident light due to the plasmonic response of deep‐subwavelength slits. To verify its polarization sensitive and broadband responses, we experimentally demonstrate two holographic patterns of an optical vortex and an Airy beam at p‐ and s‐polarized light with wavelengths of 532nm, 633nm and 780nm, respectively. Furthermore, we realize an application example of the meta‐hologram as a polarization multiplexed photonic device for multi‐channel optical angular momentum (OAM) generation and detection. Such meta‐holograms could find widespread applications in photonics, such as chip‐level beam shaping and high‐capacity OAM communication.

     

一种微型光开关的设计与仿真分析

介绍了一种新型的聚酰亚胺(PI)悬臂梁式电磁驱动微机电系统(MEMS)光开关,并对其总体结构进行了设计与仿真分析.运用有限元分析的方法,设计了永磁体的最佳尺寸并优化了悬臂梁的结构;分析了聚酰亚胺悬臂梁的扭转力、电磁力与挠度的关系.当输入电流为75 mA时,聚酰亚胺悬臂梁达到平衡时的挠度约为1.02 mm,能够满足器件转换光路的要求.     

基于ANSYS的高温超导混合磁轴承悬浮力分析

基于商用电磁场有限元软件ANSYS以及Bean临界态模型,对由圆柱形高温超导块材、永磁体和超导线圈组成的新型高温超导混合磁轴承的电磁场分布及悬浮力进行了仿真分析,研究了超导线圈对高温超导混合磁轴承悬浮力的影响,同时还通过实验测试了悬浮力。结果表明:仿真与实验具有较好的一致性,使用软件仿真方便可行,其结果较为准确可靠,可为高温超导混合磁轴承的设计和优化提供理论依据。     

ICP-AES测定邻苯二甲酸氢钾-氢氧化钠作用下土壤中重金属全量及形态分析

空白土壤作为质量控制样品,采用邻苯二甲酸氢钾-氢氧化钠进行处理土壤样品为对照,用HNO₃-HF-HClO₄混酸对土壤样品进行消化,运用等离子体发射光谱仪(ICP-AES)测定了提取处理后土壤样品中Mo, Pb, As, Hg, Cr, Cd, Zn, Cu, Ni的全量以及酸可提取态、氧化物结合态、有机结合态三种化学形态的含量。获知不同pH的邻苯二甲酸氢钾-氢氧化钠缓冲溶液对土壤中重金属全量及形态转化作用的影响。结果表明：除Pb和Zn外,投加不同pH邻苯二甲酸氢钾-氢氧化钠缓冲溶液对土壤中重金属全量的消解和测定有促进作用。邻苯二甲酸氢钾-氢氧化钠缓冲溶液对土壤中Cr, Cu, Hg, Pb的酸可提取态、对土壤中As, Hg, Pb, Zn的氧化结合态、对土壤中As和Hg的有机结合态的转化有促进作用。在pH 5.8时,Cu和Hg的酸可提取态的含量最大值分别为2.180和0.632 mg·kg-1;在pH 6.2时,Pb的氧化结合态的含量最大值为27.792 mg·kg-1;在pH 6.0时,Hg的有机结合态含量最大值为4.715 mg·kg-1。     

CsNiCl3晶体的光谱精细结构、零场分裂参量及Jahn-Teller效应

应用不可约张量理论构造了三角对称晶场中3d²/3d⁸态离子的45阶可完全对角化的微扰哈密顿矩阵，研究了CsNiCl₃晶体的光谱精细结构、晶体结构、零场分裂参量、Jahn-Telller效应以及自旋单重态对Ni²⁺离子基态能级的影响，理论与实验相符合.在此基础上，进一步研究了以前工作中被忽略的自旋-自旋耦合作用和Trees修正对CsNiCl₃晶体的光谱精细结构和零场分裂参量的影响，发现有四种机理会影响零场分裂参量：1)自旋-轨道耦合机理，2)自旋-自旋耦合机理；3)自旋-轨道与自旋-自旋联合耦合机理；4)自旋-轨道与Trees修正联合耦合机理，其中自旋-轨道耦合机理是最主要的，其他三种机理也是不可忽略的. 关键词： 基态能级 精细结构 零场分裂 自旋-自旋耦合     

小分子硫原子团簇正离子的结构稳定性

用分子图形软件设计出 4 9种硫原子团簇Sn+ (n =3～ 13)的结构 ,使用B3LYP密度泛函进行几何构型优化和振动频率计算 ,根据分子的总能量得出最稳定的同分异构体 .在硫原子团簇正离子中 ,大部分原子为二配位成键 .带有一、三配位的原子结构的总能量较高 .部分最稳定硫原子团簇正离子的构型与最稳定的中性硫原子团簇的构型完全不同 .     

调制激光场中Rydberg原子的电磁感应透明

本文主要研究了调制探测激光场中铯Rydberg 原子阶梯型三能级系统的电磁感应透明(EIT) 效应. 铯原子基态6S_1/2, 第一激发态6P_3/2 和Rydberg 态形成阶梯型三能级系统, 探测光作用于6S_1/2 (F = 4)→6P_3/2(F' = 5) 的跃迁, 耦合光在Rydberg 跃迁线6P_3/2→49S_1/2 附近扫描, 形成Rydberg 原子EIT. 当对探测光频率施加一个几kHz 的调制时, 调制解调后的EIT 信号分裂为两个峰, 双峰间距与调制频率无关,而与调制幅度导致的失谐量大小(频率调制幅度) 成正比, 双峰间隔的一半等于探测光频率调制幅度的λ_p/λ_c = 1.67 倍. 实验结果与理论计算相一致. 本文的研究结果可应用于激光线型和频率抖动的实时监测.