基于表面等离激元的金属波导全光开关设计

利用金属表面等离激元(SPP)对光波的束缚和局域增强作用,设计了一种基于金属-电介质-金属波导布拉格光栅的全光开关。根据波导的电介质材料及其结构对有效折射率的调制作用,确定了开关各结构组成部分的材料和尺寸。通过引入金属波导滤波结构对抽运光和信号光进行了有效地分离,防止了抽运光对信号光及后续光路的干扰。使用时域有限差分算法(FDTD)对开关性能进行仿真,结果表明:新设计的全光开关在抽运光的光强为50 MW/cm2时其消光比达到7.32 d B,开关响应时间小于2 ps,结构的横向尺寸约为400 nm。     

让学生看到音乐的数理之美--通过“乐音研究”再谈大学文科物理实验的设计与实施

针对新开设的大学文科物理实验“乐音研究”实验教学实践,着重强调了实验的设计理念、目的和思路。通过“乐音研究”实验,使文科学生区分噪音和乐音差异,了解其作为一种特殊力学振动的时域特征、频域特征,理解乐音“听起来好听”的悦耳和谐原理,并通过展示各个音符间的关系,让学生学会示波器以及LabView 分析界面的使用,通过分析归纳出“十二平均律”,最后利用“三分损益”方法构建管箫,体验音乐中包含物理学和数学在内的科学原理。     

Excitation of anti-symmetric coupled spoof SPPs in 3D SIS waveguides based on coupling

According to the electromagnetic field distributions, there exist two kinds of coupled spoof surface plasmon polaritons(SSPPs), the symmetric and anti-symmetric modes, in the three-dimensional(3D) subwavelength spoof–insulator–spoof(SIS) waveguide. We study the dispersion and excitation of the two kinds of coupled SSPPs supported by the 3D SIS waveguide. The evolution of the dispersion with the thickness and gap width of the waveguide is numerically investigated,and we give a theoretical analysis according to the coupling mechanism. Specially, based on the coupling mechanism,we design a zipper structure, through which the excitation and propagation of the anti-symmetric coupled modes can be realized effectively.     

等厚干涉实验中缺陷检测的数值模拟

利用数值方法研究了等厚干涉实验中平面玻璃存在凸凹缺陷时的干涉条纹,给出了不同缺陷尺寸、高度或曲率情况下的条纹变化性质,讨论了利用干涉图像进行缺陷检测的方法。该研究给出等厚干涉实验中的典型问题的数值求解办法,结果形象直观,便于理解。     

Numerical analysis of surface plasmon nanocavities formed inthickness-modulated metal－insulator－metal waveguides

The enhancement characteristics of the local field in the surface plasmon nanocavities are investigated numerically. The cavity is constructed by placing a defect structure in the thickness-modulated metal--insulator--metal waveguide Bragg gratings. The characteristic impedance based transfer matrix method is used to calculate the transmission spectra and the resonant wavelength of the cavities with various geometric parameters. The finite-difference time-domain method is used to obtain the field pattern of the resonant mode and validate the results of the transfer matrix method. The calculation and simulation results reveal the existence of resonant wavelength shift and intensity variation with structural parameters, such as the modulation period of the gratings, the length and the width of the defect structure. Both numerical analysis and theoretical interpretation on these phenomena are given in details.     

用于CSRe上16O5+离子精密激光谱学实验的极紫外光子探测系统的研制

高电荷态离子的精密谱学研究不仅为强场QED效应、相对论效应、电子关联效应等基础前沿理论模型的精确检验提供了良好的条件,而且对同位素移动、高电荷态离子光钟等诸多前沿物理研究具有重要意义。为了在兰州重离子加速器冷却储存环的CSRe上开展相对论能量类锂16O5+离子2s_1/2→2p_1/2和2s_1/2→2p_3/2光学跃迁精密测量的激光谱学实验研究,研制了一套适用于前向发射荧光收集测量的新型非拦截式极紫外光子探测系统。该探测系统主要由抛物面型SiC反射镜、镀有CsI的微通道板(MCP)探测器以及高速步进电机等部分组成。在CSRe的高温烘烤环境和超高真空实验环境下,该探测系统能够在不影响储存环内离子束正常运转的同时实现对极紫外波段(50~200 nm)前向发射光子的高效探测,其探测效率较CSRe上现有光子通道倍增管荧光探测器提升约50倍。该探测系统不仅能够为CSRe上高电荷态离子的精密激光谱学实验提供高效实时的探测工具,亦为将来在大科学装置HIAF上开展更高能量、更高电荷态重离子的精密激光谱学实验研究奠定了坚实的基础。