基于单负超材料的高品质因数亚波长谐振腔

首先对由两种单负超材料组成的异质结的传输特性进行了研究,发现该异质结具有谐振腔功能和亚波长特性。然后对该亚波长谐振腔品质因数的增强进行了研究,发现当在由两种单负超材料组成的异质结界面处引入类电磁感应透明超材料原胞时,谐振腔的品质因数得到大幅增强,从而获得了一种具有高品质因数特点的亚波长谐振腔。该谐振腔将有助于微波及更高频段元器件的小型化。     

亚波长周期性排列空气孔的传输特性研究

从实验和理论两方面来研究了亚波长样品中周期变化时对透过曲线的影响.首先,利用聚焦离子束刻蚀方法和电子束直写系统制备了实验样品:正方和六角晶格空气孔及H-形空气槽.然后,研究了正方和六角晶格空气孔在可见光及近红外波段周期性对透过曲线的影响,证明表面等离子体对透过曲线的增强作用.测量了H-形空气槽在近红外波段的透过曲线,通...     

一种金属亚波长缝槽结构的高方向性辐射研究

本文设计了一种基于银-铝-银复合膜层结构的金属亚波长缝-槽结构。该结构由亚波长狭缝和周期性沟槽组成，在632.8 nm波长下，可实现远场的高方向性辐射。文中用有限元法分析了狭缝宽度、沟槽深度和沟槽周期对出射光高方向辐射特性的影响，并据此优化得到了器件的结构参数。使用搭建的光学远场测试平台对该缝-槽结构进行测试发现，结构的远场发散角约为4.1°，测量结果与仿真结果基本吻合，进一步证实结构的远场高方向性辐射特性。     

基于X光光刻的亚波长光栅

描述了一种新的亚波长光栅的微细加工技术,即X光光刻得到相应的亚微米级的线宽图形,再利用显影技术获得了高深宽比的立体亚波长光栅．用此纳米加工技术获得了栅距为500nm、250nm、150nm,光栅高度为1900nm的特殊纳米光栅模具,开发了纳米无反射结构,并研制成功了亚波长光栅．该亚微米线宽微细加工技术可用于布拉格光栅、DVD读写头、无反射表面等需要亚微米结构的器件中．     

二维亚波长结构石英紫外压印模板的制备

利用紫外光刻和反应离子刻蚀技术在石英衬底上制备二维亚波长结构的压印模板,并对模板进行表面修饰.研究了主要刻蚀工艺参数对刻蚀速率及刻蚀形貌的影响.增加工作气压,刻蚀速率先增大到最大值,然后下降;增加射频功率可以提高刻蚀速率,但功率过大会导致刻蚀产物发生二次沉积;延长刻蚀时间可以增加刻蚀深度,但时间过长会发生过刻蚀现象.在优化的刻蚀工艺条件下制备出了较为理想的亚波长石英模板.经表面修饰后,模板表面与水的接触角增大,有效克服了压印胶的粘连,并在ZnS衬底上压印出了良好的二维亚波长结构图形.     

亚波长圆孔近场分布特性研究

采用三维时域有限差分法对单色平行光透过亚波长圆孔后的电磁场分布进行计算,计算距圆孔出射端口几个纳米范围内的瞬时光场分布,结果发现:虽然入射光沿y方向偏振,但由于介质的不连续性,在光的传播过程中产生分别沿、方向偏振的电场分量和;在与入射光偏振方向垂直的边缘处显示出明显的场增强现象。     

亚波长径向偏振光栅的设计

针对现有电力光学电流传感中法拉第旋转角的非线性测量、解调模式的光强依赖性等问题,本文设计了一种环型亚波长偏振光栅,其光栅矢量径向分布,可将偏振光的偏振分布转化为光斑强度分布并与偏振面同步旋转。应用琼斯矩阵对其偏振特性进行分析,运用严格耦合波理论对光栅进行仿真分析与优化设计,并制备了辐射状的环型铝金属光栅。测试结果表明,光栅TM光的透过率大于80%、整体消光比大于100,可实现对光偏振态的直接检测,并具有线性测量范围大、测量结果不依赖于光的绝对强度等优点,可用于基于图像分析的偏振检测技术。     

银纳米片的绿色化学法合成及其光学性能研究

结合简便且绿色的方法,在单宁酸体系中制备出银纳米片。该化学反应无需热源,也不需要引入其他任何表面活性剂和形貌控制剂,故是一种能耗低、对环境绿色友好的策略。采用透射电镜、X射线衍射仪、紫外可见分光光度计等测试手段对样品进行分析和表征。系统优化制备银纳米片中单宁酸浓度及溶液pH值的工艺参数,实现了银纳米片的SPR峰从520...     

亚微米聚焦离子束的漂移现象

研究李亚微米聚离子束（ＦＩＢ）系统的漂移现象，给出了测量漂移的方法，分析引起漂移的原因及降低漂移的措施，发现了偏转电极上的钝化层及污染物充电电荷所引起的漂移现象；测出了各电极电压变化所引起民漂移的大小；发现了由于外壳温度不均匀引起离子枪轴线相对样品变化所引起的漂移。提出了制作透镜电极时保持轴对称、特别是限制光栏必须位于透镜光轴的必要性。所给出的数据漂移数据既包含早期的单组透镜ＦＩＢ系统的数据，也包     

Subwavelength diffraction in a limited number of metal waveguide arrays

Subwavelength diffraction in a limited number of nanostructured metal waveguide arrays has been investigated. We use a new method to derive the coupling constant. Perturbation approach and supermode theory are employed to obtain the solution for propagation constants and wave functions. The distributions of the field intensity with propagation distance are obtained accurately. Our theories are verified by the finite-difference time-domain method. Numerical simulation results show a good agreement with the theoretical predictions.     

Analysis of the extraordinary transmission properties of arrays of subwavelength holes on a metal film in the terahertz region

The extraordinary transmission properties of terahertz waves through arrays of subwavelength holes on a metal film have been investigated. The effects of the geometrical parameters and dielectrics filling the hole on transmission properties have been explored. The results show that the resonance peak shifts to long wavelength as the hole width and lattice period constant increase. As the refractive index of the dielectric materials filling the hole increases, the transmittance increases and the resonance peak wavelength changes to low frequency. The phase retardation can be flexibly changed by varying the geometrical parameters and dielectric materials filling in the hole.     

Interactions between Fabry–Pérot and nanohole resonances in metallo-dielectric plasmonic nanostructures

We present results of numerical simulations for structures comprised of metallo-dielectric layers in which the metal layers are perforated with non-diffracting arrays of subwavelength holes, structures that are similar to the ‘fishnet’ structures being studied as electromagnetic metamaterials. We find for visible frequencies that such structures exhibit a stop-band in transmittance across a broad frequency range, which arises through interactions between two distinctly different types of resonant mode. Using numerical (finite element) modelling to characterise the optical response, we identify strong coupling between Fabry–Pérot resonant cavity modes within the multilayer structure and localised surface-plasmon resonances associated with the nanoholes. Our simulations show that the spectral position and width of the stop-band that occurs within the visible frequency range can be tuned by varying both the cavity spacing and the geometry of the nanohole array.     

Review on subwavelength confinement of light with plasmonics

In this review, an overview of the subwavelength confinement of light with plasmonics is presented. Among the varieties of state-of-the-art technologies on this intensively-studied topic, we focus on the surface plasmon-assisted light enhancement via the single metallic aperture. Based on a systematic overview of the physical principles of light enhancement in subwavelength-sized metallic apertures, we investigate various types of apertures and discuss their characteristics.     

Bunched electron beam properties measurement by means of single-shot multibeam cross-correlation technique

A new single-shot multibeam cross-correlation technique is proposed for the measurement of a bunched electron beam temporal structure. As an optical laser pulse modulated by the Coulomb field of the electron bunch in an electro-optical crystal, it is proposed to use a non-uniform pulse modulated both in time and in space. In the proposed technique, measurement of the time profile is realized during a single laser shot. In this case, as a result of electro-optical modulation of a non-uniform femtosecond pulse, the information on the time profile of the Coulomb field is contained in only the spatially shifted spectral components of the modulated pulse.     

高Q平面环形微腔的制备以及测试

采用MEMS工艺制备平面微盘腔,再通过二氧化碳激光熔融其表面形成为环状结构,通过三维形貌微系统分析仪、原子力显微镜分别测试了其外部尺寸和表面粗糙度,实验结果表明,锥形光纤近场耦合测得微腔品质因素为4.8×105,耦合效率在95%以上,因此激光回流微的方式在得到了新的结构的同时保证了光腔的性能。