超宽带高吸收超材料太阳能吸收器设计

基于阻抗匹配理论与组合谐振结构特性,设计了一种超宽带超材料太阳能吸收器。该吸收器由栅格结构与金属/介质/金属堆叠结构组合而成,组合结构有效拓展了吸收带宽。采用时域有限差分法分析了吸收器的吸收特性,结果表明：该吸收器在300～4000 nm波段内的平均吸收率可达94.9%,吸收带宽为3700 nm,可有效覆盖可见光与红外光波段。该吸收器在整个吸收波段范围内具有一定的偏振独立特性,以60°广角斜入射时,平均吸收率仍可达到93%。谐振频点处的电磁场分布表明,该吸收器的超宽带高吸收特性主要归因于表面等离子体共振、局域表面等离子体共振、慢波效应、法布里-珀罗共振,以及共振模式间的杂化耦合作用。所提超宽带高吸收太阳能吸收器在许多超材料领域具有潜在的应用价值。     

基于金属铑和二氧化硅材料的紫外线超宽带吸收器

设计了一种基于金属铑（Rh）和二氧化硅（SiO2）材料的紫外线吸收器,其单元结构由Rh衬底、SiO2电介质层和Rh图案层构成。采用有限元方法（FEM）分析了该吸收器的吸收特性与入射波波长、入射角、方位角和几何结构参数的依赖关系。结果表明,该紫外线吸收器通过表面等离子体共振效应达到吸收目的。通过调整单元结构的几何参数,可以调整该吸收器的吸收特性。由于结构的旋转对称性,该吸收器具有偏振不敏感性。在所有结构参数均采用最优值的情况下,当入射角为0°～45°、波长为200～400 nm时,均能获得90%以上的高吸收率。吸收率为95%的波段为250～300 nm及325～400 nm。所设计的紫外线超宽带吸收器具有优良的吸收性能。采用的Rh金属为紫外波段内吸收材料的选择提供了新的选项。研究结果为紫外线吸收器的设计、制作和应用提供了参考。     

基于双层VO2的可调谐宽带太赫兹超材料吸收器

基于VO₂的相变特性,提出一种具有宽带特性的太赫兹超材料吸收器,包括2层VO₂图案、2层聚酰亚胺介电层和1层金属反射层,共5层结构。对吸收器的吸收特性、电场分布和可调谐特性进行仿真分析,结果表明,所设计的吸收器吸收率大于90%的带宽为2.56 THz。该吸收器将2层结构相同但尺寸不同的周期单元堆叠,有效扩展了带宽;且通过控制VO₂从绝缘态到金属态的相变,可以实现吸收率的连续调谐。通过研究不同偏振角及入射角条件下所设计超材料吸收器的吸收性能发现,该吸收器具有偏振无关、在较大入射角入射时吸收不敏感特性。所设计的吸收器有望在太赫兹通信、成像和探测器等领域得到广泛应用。     

一种四通道吸收器优化设计研究

本文基于阻抗匹配原理和表面等离子体共振理论,设计了一种石墨烯-MIM结构-金属铝(Al)底板三层结构超材料吸收器.采用时域有限差分法FDTD研究和分析了吸收器的共振吸收光谱,电磁场能量分布,并优化了设计结构.研究结果表明,该吸收器具有近红外波段四个超窄带吸收峰;最大吸收率可达0.943,3 dB带宽均为3.55 μm左...     

基于复合凹槽的光栅型红外线吸收器

设计了一种基于LiF和NaF材料的复合凹槽的光栅型红外吸收器.采用频域有限差分法(FDFD)分析了这种吸收器的吸收机理,以及结构参数、入射波的波长和入射角度对其吸收特性的影响.结果表明,对于入射的不同波长的红外线,这种吸收器会形成不同的光学谐振腔,能够在较宽的波长范围内对红外线形成强烈的吸收.在采用优化参数的条件下,在18~70μm的波长范围和0~80°的入射角范围内,这种吸收器具有良好的吸收效果.文章的研究工作给光栅型红外线吸收器的设计、制作和应用提供了理论基础.     

基于圆顶锥壳阵列的超宽带太阳能吸收器研究

提出了一种顶锥壳阵列超宽带全向超材料吸收器,研究了圆顶锥壳的几何参数、顶部的几何形状以及不同密排方式对宽带吸收的影响.研究了包覆金属薄膜的圆顶锥壳阵列在太阳辐射能谱区的超宽带吸收特性,结果显示在250～2 500 nm范围内的平均吸收率达到95.39％.在0°～65°的大角度入射下,对于TE和TM偏振的平均吸收率分别为92.7％和94.59％,表明所提出的结构具有偏振无关和入射角不敏感性.空气质量1.5加权平均吸收率为95.24％,证明能够有效地吸收地球上的太阳辐射.通过结合胶体球光刻技术和表面镀膜成功制备了所提出的吸收器,初步测试结果表明,其吸收性能存在提升空间.     

基于二氧化钒的动态可调谐的红外线超宽带吸收器

设计了一种基于二氧化钒的动态可调谐的红外线超宽带吸收器。数值模拟表明：对于横磁(TM)波,当入射角由0°增加到60°时,在17～55μm波长范围内,吸收器的吸收率可以保持在90%左右;对于横电(TE)波,当入射角由0°增加到55°时,在10～55μm波长范围内,依然可以实现90%左右的高效吸收;当TM波或TE波垂直入射时,在16～60μm波段,吸收率大于90%,吸收带宽可以达到54μm。当二氧化钒的电导率从20 S/m逐渐变化到2×10⁵ S/m时,超宽带吸收器可转换为多峰吸收器。与之前报道过的基于二氧化钒的吸收器相比,所设计的吸收器的带宽和可调性得到了显著改善。该吸收器有望在偏振探测器、热辐射器、红外传感器等领域中得到应用。     

基于VO2、NaF和TiO2材料的红外线超宽带吸收器

设计了一种基于VO₂、NaF和TiO₂材料的红外线超宽带可调吸收器,并采用有限元方法对其吸收特性进行了分析。结果表明：当入射波垂直入射时,吸收率对偏振角不敏感。在21～25μm及35～43μm波长范围内,吸收率可以达到99.8%。在12～51μm范围内,吸收率可以达到90%。在0～55°入射角范围内,横磁(TM)波在12～52μm波长范围内,横电(TE)波在20～45μm波长范围内,吸收率均可达到80%以上。获得宽带吸收的主要原因是表面等离子体共振效应。通过改变VO₂的电导率,可以调节吸收器的吸收率,实现吸收率的可调性。所设计的红外线超宽带吸收器具有优良的吸收性能,在传感、探测及能量收集和转化等方面具有潜在的应用价值。     

基于二氧化钒的可调宽带太赫兹完美吸收器设计

本文设计了一种可动态调节的宽频太赫兹完美吸收器,该吸收器由十字形的二氧化钒层、金属接地平面和夹在中间的二氧化硅层组成.仿真结果表明,90％以上的吸收带宽为1.06 THz,范围为0.71～1.77 THz.吸收率随二氧化钒电导率的变化而变化,可在4％～99.5％之间动态调节.为了得到吸收器工作的物理机理,引入了阻抗匹配理论和波干涉理论,并通过电场分布分析了两个完美吸收峰的物理来源.该吸收器具有广角吸收和偏振不敏感的特点.该吸收器可以用于太赫兹传感器、探测器和隐身装备等.     

偏振选择可调谐双带太赫兹吸收器

提出并研究了一种偏振选择可调谐双带太赫兹吸收器。吸收器由顶层方形劈裂石墨烯环、中间SiO₂介质层以及底层金反射层组成。基于时域有限差分法的仿真结果显示,该吸收器在不同偏振光入射下均可以实现双带高效率吸收。x偏振光时在7.86和12.63THz处的吸收率分别为97.9%和91.2%;y偏振光时在6.30和10.52THz处的吸收率分别为94.1%和93.2%。通过改变石墨烯费米能级,可以对两个偏振的双带吸收峰波长进行调谐。此外,研究了介质层厚度和石墨烯劈裂环的物理参数对共振吸收峰的影响。因为在两个偏振状态下都能产生双带高吸收,所以此吸收器在太赫兹偏振成像、太赫兹传感、选择性光谱检测和偏振复用等领域有重要的潜在应用价值。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.