磁场中激光牵引热解石墨的理论与实验研究

利用钕铁硼永磁体搭建了悬浮平台,抗磁性物质热解石墨片做悬浮物,在光热效应下,研究了激光牵引磁悬浮热解石墨的运动机制.从悬浮物受力公式出发,将其分为磁场与热场2部分影响,结合Matlab给出理论公式与实验方案,通过实验验证了理论的自洽性.使用COMSOL进行数值模拟,给出定位情况下的受力情况、磁场分布以及热场分布等.使用COMSOL建立了相关APP,可以得到磁铁序列的磁场分布、势场分布、热解石墨片的热场分布及其在磁场中任意位置的受力.     

Self-assembly 2D plasmonic nanorice film for surface-enhanced Raman spectroscopy

As an ultrasensitive sensing technology, the application of surface enhanced Raman spectroscopy (SERS) is one interesting topic of nano-optics, which has huge application prospectives in plenty of research fields. In recent years, the bottleneck in SERS application could be the fabrication of SERS substrate with excellent enhancement. In this work, a two-dimensional (2D) Ag nanorice film is fabricated by self-assembly method as a SERS substrate. The collected SERS spectra of various molecules on this 2D plasmonic film demonstrate quantitative detection could be performed on this SERS substrate. The experiment data also demonstrate this 2D plasmonic film consisted of anisotropic nanostructures has no obvious SERS polarization dependence. The simulated electric field distribution points out the SERS enhancement comes from the surface plasmon coupling between nanorices. And the SERS signals is dominated by molecules adsorbed at different regions of nanorice surface at various wavelengths, which could be a good near IR SERS substrate for bioanalysis. Our work not only enlarges the surface plasmon properties of metal nanostructure, but also exhibits the good application prospect in SERS related fields.     

向列相溶致液晶旋转黏度研究

溶致液晶具有良好的生物相容性、无毒性、生物降解性以及光学、电磁学各向异性等, 在细胞相互作用、神经刺激传递、脂肪吸收、药物智能输运等生命活动研究、医药工程和液晶显示等领域有广泛应用. 本文采用旋转磁场法测得溶致液晶日落黄在不同温度和溶液浓度下向列相时旋转黏度, 并结合溶致液晶分子自组装过程, 理论分析了溶致液晶向列相旋转黏度随温度和溶液浓度的变化规律. 研究结果表明: 溶致液晶旋转黏度与液晶分子自组装柱状体平均长度的平方呈正比增大关系, 随溶液浓度的增大而增大, 随温度的升高表现出指数减小的规律. 构建了与向列相溶致液晶温度和浓度相关的旋转黏度经验表达式, 经验表达式计算结果与实验值吻合较好, 最大误差仅为18.56${\%}$. 提出采用旋转流变仪间接获得溶致液晶剪切能的新方法, 溶致液晶剪切能随溶液浓度的增大而增大, 但在实验温度范围内, 溶致液晶剪切能几乎不随温度而改变. 利用旋转流变仪间接获得的溶致液晶剪切能与报道的利用X-Ray检测所得的结果之间最大误差仅为3${\%}$. 成功地利用了液晶分子自组装能力随温度的变化规律来研究柱状体长径比对旋转黏度的影响规律, 创新地提出了"一步法"测量研究, 大大减少相关实验研究的成本和复杂性.      

保偏等离激元纳米光波导、等离激元纳米光子路由器和多路转接器评述

从上世纪中叶发展起来的信息技术,革命性地改变了人们的社会生活方式和经济增长模式.然而,随着现代加工工艺的不断进步和电子器件集成化程度的提高,电子芯片的物理瓶颈,如量子尺寸效应和热效应等,对目前信息技术的发展将有着不可避免的制约.而光子作为信息的载体有着电子无法比拟的优势,如高带宽、高密度、高速度和低耗散等,光信号传输速度比电子快1000倍,而且光信号可以携带强度、偏振、相位和频率等信息,可以突破二进制的限制.     

Near-Infrared Properties of Hybridized Plasmonic Rectangular Split Nanorings

The near-infrared properties of gold rectangular split nanorings （RSNs） are investigated by simulation using the finite element method. In the results, the distribution and enhancement of electromagnetic （EM） fields are confirmed by the distribution of charge and current density. The spectrum variation with split distance of RSNs in absorption is in accordance with the hybridization theory. The influence of split distance and light wavelength on the enhancement of EM field is also studied for devices that make use of surface plasmon resonance in nearinfrared, such as in optical trapping, biomedicine, and solar energy. Additionally, the spectra in mediums with various refractive indices suggest the potential application of the hybridized plasmonic RSNs as an ultra-sensitive sensor in the near-infrared region.     

Light focusing in linear arranged symmetric nanoparticle trimer on metal film system

Benefiting from the induced image charge on film surface,the nanoparticle aggregating on metal exhibits interesting optical properties.In this work,a linear metal nanoparticle trimer on metal film system has been investigated to explore the novel optical phenomenon.Both the electric field and surface charge distributions demonstrate the light is focused on film greatly by the nanoparticles at two sides,which could be strongly modulated by the wavelength of incident light.And the influence of nanoparticle in middle on this light focusing ability has also been studied here,which is explained by the plasmon hybridization theory.Our finding about light focusing in nanoparticle aggregating on metal film not only enlarges the novel phenomenon of surface plasmon but also has great application prospect in the field of surface-enhanced spectra,surface catalysis,solar cells,water splitting,etc.