A high figure of merit localized surface plasmon sensor based on a gold nanograting on the top of a gold planar film

We investigate the sensitivity and figure of merit （FOM） of a localized surface plasmon （LSP） sensor with gold nanograting on the top of planar metallic film. The sensitivity of the localized surface plasmon sensor is 317 nm/RIU, and the FOM is predicted to be above 8, which is very high for a localized surface plasmon sensor. By employing the rigorous coupled-wave analysis （RCWA） method, we analyze the distribution of the magnetic field and find that the sensing property of our proposed system is attributed to the interactions between the localized surface plasmon around the gold nanostrips and the surface plasmon polarition on the surface of the gold planar metallic film. These findings are important for developing high FOM localized surface plasmon sensors.

A Novel Method of Testing Aspherical Surface

A set-up based on a special shadow method, pinhole method, was made and some experiments were done. The results show that this novel method is simple, easy to operate,and suitable for testing large aspherical surfaces quantitatively.

Severe prelenticular membrane formation on the surface of a hydrophilic acrylic intraocular lens after cataract surgery in an eye with an Ahmed valve implant

【正】Dear Sir,Iam Yong-Sun Ahn,from the Department of Ophthalmology of St.Vincent Hospital of Suwon,Kyungki-do,South Korea.Cataracts are a common problem in eyes with a glaucoma drainage device(GDD),because tube shunt surgery increases the incidence and progression of cataracts[1].An Ahmed valve,the most commonly inserted GDD,is composed of a silicone tube connected to a flat plate sewn to the sclera,and aqueous humor flows from the

Performance analysis of surface plasmon resonance sensor with high-order absentee layer

A surface plasmon resonance （SPR） sensor with a high-order absentee layer on the top of metallic film is proposed. The performance of the SPR sensor with NaCl, MgO, TiO2 or AlAs high-order absentee layer is analyzed theoretically. The results indicate that the sensitivity and the full width at half maximum of those SPR sensors decrease with the increasing of the order of absentee layer, but the variation of the figure of merit （FOM） depends on the refractive index of absentee layer. By improving the order of absentee layer with high-refractive-index, the FOM of the SPR sensor can be enhanced. The maximum value of FOM for the SPR sensor with high-order TiO2 （or AlAs） absentee layer is 1.059% （or 2.587%） higher than the one with one-order absentee layer. It is believed the proposed SPR sensor with high-order absentee layer will be helpful for developing the high-performance SPR sensors.

Enhancing surface adhesion of polytetrafluoroethylene induced by two-step in-situ treatment with radiofrequency capacitively coupled Ar/Ar+CH_(4)+NH_(3) plasma

Although some progress in plasma modification of the polytetrafluoroethylene(PTFE) surface has been made recently,its adhesion strength still needs to be further improved.In this work,the surface of a PTFE sample was treated with a two-step in-situ method.Firstly,the PTFE surface was treated with capacitively coupled Ar plasma to improve its mechanical interlocking performance;then,Ar+NH_(3)+CH_(4) plasma was used to deposit an a-CNx:H cross-linking layer on the PTFE surface to improve the molecular bonding ability.After treatment,a high specific surface area of 2.20 and a low F/C ratio of 0.32 were achieved on the PTFE surface.Its surface free energy was increased significantly and its maximum adhesion strength reached77.1 N·10 mm^(-1),which is 56% higher than that of the single-step Ar plasma-treated sample and32% higher than that of the single-step Ar+CH_(4)+NH_(3) plasma-treated sample.

Enhanced surface-insulating performance of EP composites by doping plasmafluorinated ZnO nanofiller

The surface flashover of epoxy resin(EP) composites is a pivotal problem in the field of highvoltage insulation.The regulation of the interface between the filler and matrix is an effective means to suppress flashover.In this work,nano ZnO was fluorinated and grafted using lowtemperature plasma technology,and the fluorinated filler was doped into EP to study the DC surface flashover performance of the composite.The results show that plasma fluorination can effectively inhibit the agglomeration by grafting –CFxgroups onto the surface of nano-ZnO particles.The fluorine-containing groups at the interface provide higher charge binding traps and enhance the insulation strength at the interface.At the same time,the interface bond cooperation caused by plasma treatment also promoted the accelerating effect of nano ZnO on charge dissipation.The two effects synergistically improve the surface flashover performance of epoxy composites.When the concentration of fluorinated ZnO filler is 20%,the flashover voltage has the highest increase,which is 31.52% higher than that of pure EP.In addition,fluorinated ZnO can effectively reduce the dielectric constant and dielectric loss of epoxy composites.The interface interaction mechanism was further analyzed using molecular dynamics simulation and density functional theory simulation.

Ionization wave propagation and cathode sheath formation due to surface dielectric-barrier discharge sustained in pulsed mode

This work deals with the experimental study of a surface dielectric-barrier discharge,as a part of the ongoing interest in the control of plasma induced electro-fluid dynamic effects(e.g.plasma actuators).The discharge is generated using a plasma reactor consisting of a fused silica plate which is sandwiched between two printed circuit boards where the electrodes are developed.The reactor is driven by narrow high voltage square pulses of asymmetric rising(25 ns)and falling(2.5μs)parts,while the discharge evolution is considered in a temporarily and spatially resolved manner over these pulses.That is,conventional electrical and optical emission analyzes are combined with high resolution optical emission spectroscopy and ns-resolved imaging,unveiling main characteristics of the discharge with a special focus on its propagation along the dielectric-barrier surface.The voltage rising part leads to cathode-directed ionization waves,which propagate with a speed up to 105m s~(-1).The voltage falling part leads to cathode sheath formation on the driven electrode.Τhe polarization of the dielectric barrier appears critical for the discharge dynamics.

全口径环形抛光的光学元件面形误差影响因素及其控制

全口径环形抛光是加工大口径平面光学元件的关键技术之一,其瓶颈问题是元件面形的高效高精度控制。通过研究元件面形的影响因素及其控制方法从而提升其确定性控制水平。围绕影响面形误差的运动速度、抛光盘表面形状误差和钝化状态等关键工艺因素,建立基于运动轨迹有效弧长的环形抛光运动学模型,揭示了抛光盘表面开槽槽型对面形误差的影响规律;提出了采用位移传感器以螺旋路径扫描抛光盘表面并通过插值算法生成其形状误差的方法,建立基于小工具的子口径修正方法,实现了抛光盘形状误差的在位定量修正;提出抛光盘表面钝化状态的监测方法,研究了抛光盘表面钝化状态对面形误差的影响规律。结果表明:抛光盘表面开槽采用环形槽时元件表面容易产生环带特征,采用径向槽、方形槽和螺旋槽时元件表面较为匀滑;通过在位定量检测和修正抛光盘形状误差,可显著提升元件的面形精度;随着抛光盘表面的逐渐钝化,元件面形逐渐恶化。在研制的5 m直径大口径环形抛光机床上加工800 mm×400 mm×100 mm平面元件的面形PV值优于λ/6(λ=632.8 nm),提升了元件的面形控制效率和精度。

拉锥光纤表面等离激元共振高性能传感器

Au和Ag常用于激发表面等离激元共振(SPR)。Ag的欧姆损耗低于Au,损耗谱线更窄,但Ag容易被氧化。而TiO_(2)具有化学稳定性和可调性等优势。因此,为了做出性能优异且稳定的传感器,提出了一种基于Ag/TiO_(2)的拉锥多模光纤(MMF)表面等离激元共振传感器。TiO_(2)增加传感器灵敏度保留了窄损耗谱线的优势,同时起到了保护Ag免受氧化的作用。该传感器具有高灵敏度和高质量指数(FOM)的特点,在通信波长范围内表现出卓越性能。为了深入研究,文中使用基于COMSOL Multiphysics软件的有限元方法(FEM)模拟工具进行了数值研究。模拟结果显示:传感器实现了最大波长灵敏度达到16000 nm/RIU,最大FOM值为1920 RIU^(-1)。该研究为高性能SPR传感器的设计提供了有价值的设计见解。

一种大径厚比低温分光片支撑结构的设计与试验

空间相机大径厚比低温分光片支撑结构设计时,需要在刚度和柔度方面进行平衡,既要保证能通过力学振动考核,同时还要保证低温下面形精度。针对这一需求,文章设计了一种新的支撑结构,利用不同结构材料热膨胀系数差异进行变形适配,实现无热化支撑,同时在不同材料连接环节设计多级径向柔性卸载结构,实现分光片高刚度、高低温面形精度支撑。对该结构进行了仿真分析,结果表明:分光片组件一阶基频达到191 Hz,从常温293 K到工作温度133 K,分光片面形RMS变化0.032λ(λ=632.8 nm)。该结构的低温面形测试结果显示:温度从293 K降到130 K,分光片面形RMS变化0.028λ。分光片组件随相机主体完成鉴定级力学试验考核,分光片组件安装点最大加速度响应达到16gn,试验前后分光片组件状态无变化。文章设计的大径厚比低温分光片支撑结构刚度、低温面形精度和环境适应性均满足空间相机应用要求。

固结磨料小工具头修形抛光钛合金叶片试验研究

为了提高非均匀余量钛合金叶片的表面质量及轮廓精度,提出基于固结磨料小工具技术的钛合金叶片修形与抛光一体化的新方法,根据叶片加工的理论轨迹点与实际测量点之间的空间相对位置关系得到钛合金叶片的加工余量分布情况。基于确定性抛光原理创建叶片表面定量去除模型,在机器人恒力抛光平台上进行钛合金叶片修形抛光试验。试验结果表明:钛合金叶片叶盆的平均粗糙度从起始的0.924μm下降到0.225μm,叶背的平均粗糙度从起始的0.984μm下降到0.249μm,均达到了小于0.4μm的加工要求;叶片表面原有的凹坑和划痕被有效去除,加工后表面没有明显的缺陷,纹理致密均匀;抛光后的叶片轮廓度误差小于叶片所允许的-0.05~0.05 mm误差范围。从而验证了固结磨料小工具头修形抛光非均匀余量钛合金叶片的可行性,为航空发动机叶片的修形与抛光的工艺选择提供了参考依据。

绝缘子表面电场及电荷的测量

绝缘子表面电荷积聚及其引起的表面电场分布畸变是导致绝缘子表面闪络电压低的主要原因。对绝缘子表面电场及电荷分布进行测量有助于正确地设计绝缘子。为此,在阅读大量相关文献及进行技术调研的基础上,结合作者目前正在进行的研究,对绝缘子表面电场及电荷的测量技术进行了综述。首先简要分析了绝缘子表面电荷的来源(场致发射、局部放电、固体介质夹层极化、电导率分布不均匀或非线性、表面金属微粒等),然后详细介绍了几种绝缘子表面电荷及电场的测量技术,包括静电探头法(有源静电探头和无源静电探头)、粉尘图法、电光法(克尔效应和普克尔斯效应),最后分析了这几种方法的优缺点。

反应烧结碳化硅平面反射镜的光学加工

介绍了100mm口径反应烧结碳化硅平面反射镜的光学加工工艺流程。按照流程依次介绍了在粗磨成形、细磨抛光和精磨抛光过程中使用的机床、磨具和磨料以及采用的工艺参数和检测方法。介绍了在光学加工各个步骤中应注意的问题。展示了加工后反应烧结碳化硅平面反射镜的实物照片。给出了面形精度和表面粗糙度的检测结果:面形精度(95%孔径)均方根值(RMS)为0.030λ(λ=632.8nm),表面粗糙度RMS值达到了1.14nm(测量区域大小为603 6μmⅹ448 4μm)。

反应烧结碳化硅球面反射镜的光学加工与检测

介绍了250mm口径、4200mm曲率半径的反应烧结碳化硅球面反射镜光学加工和检测的工艺流程;并按照流程依次介绍了在研磨成型、细磨抛光和精抛光过程中使用的机床、磨具、磨料及采用的工艺参数和检测方法。介绍了在光学加工和检测各个步骤中应注意的问题。展示了加工后250mm口径反应烧结碳化硅球面反射镜的实物照片,并给出了面形精度和表面粗糙度的检测结果:面形精度(95%孔径)均方根值(RMS)为0.037波长(λ=632.8nm),表面粗糙度RMS值达到1.92nm(测量区域大小为603.6ⅹ448.4μm)。

高精度轻型长条形反射镜多点支撑方案

轻型、大视场、高分辨力可见光空间遥感器的研制已成为空间光学工作者的重点研究课题。本文结合某研究项目拟探讨高精度长条形反射镜的多点支撑方案及其实施，重点论述其研究过程和方法。

碳化硅扫描反射镜支撑结构设计

对尺寸为460 mm×290 mm的SiC扫描反射镜的轻量化和支撑结构的设计进行了研究。基于三角形和矩形的复合轻量化结构,采用镜体背部为开放和封闭相结合的形式,设计了一种新型的扫描反射镜组件。该组件采用侧面支撑方式和轴向柔性结构,有利于消除支撑结构材料热膨胀系数不匹配产生的热应力对镜面面形的影响。有限元方法分析结果表明:反射镜组件在1 g重力载荷和8℃温度变化作用下,反射镜镜面的面形误差RMS值分别为4.5 nm和20.3 nm。该反射镜轻量化形式和支撑结构满足光学成像要求,并可有效提高结构的稳定性,对于大尺寸反射镜组件的设计具有借鉴意义。

离子束作用下的光学表面粗糙度演变研究

为了获得超光滑光学表面,介绍了离子束作用下改善表面粗糙度的抛光方法,并通过相关的实验进行了验证。光学材料是典型的硬脆材料,在加工过程中的表面粗糙度要经历复杂的演变过程。离子束加工作为光学镜面加工中的最后一道工序,如果在修正面形的同时,能够有效地改善表面粗糙度,那么离子束加工的性能就可以得到更好的延伸。分析了离子束作用下的粗糙度演变机理,在此基础上提出了倾斜入射抛光和牺牲层抛光技术2种改善表面粗糙度的方法,并使用原子力显微镜进行了测量。实验结果表明:以45°倾斜入射抛光熔石英样件,其粗糙度由初始的0.67 nm RMS减小到0.38 nm RMS;涂上牺牲层的材料表面粗糙度由0.81 nm RMS减小到0.28 nm RMS,倾斜入射抛光和牺牲层抛光技术能够有效地改善表面粗糙度。

表层残余应力对几何形体热变形的影响

机械设备在运行过程中由于运动副中的摩擦与热源的作用，各零部件将产生热变形．热变形的大小受零件的形状、材料以及表层残余应力等因素的影响．该文以简单的几何形体——厚壁长圆筒为例，着重分析了表层残余应力对几何形体热变形的影响，这种影响在超精密加工和纳米技术中是不能忽略的．

轻质碳化硅平面反射镜超光滑表面加工

介绍了对角线为110mm六边形反应烧结轻质碳化硅平面反射镜超光滑光学加工工艺流程。详细阐述了各个工序所使用的磨具、磨料和抛光机床工艺参数,对实际加工的轻质碳化硅平面反射镜超光滑表面进行检测,检测结果为:面形精度均方根值(RMS)为0.011λ(PV值为0.071,λ=632.8nm),表面粗糙度RMS达0.75nm。

碳化硅光学镜面加工

简要介绍了碳化硅光学镜面的主要应用领域;碳化硅材料的主要物理特性和几种常用的制备方法;比较了碳化硅材料与其他常用光学镜面介质材料的主要物理性质。介绍了碳化硅光学镜面的光学加工的流程和加工手段;比较分析了碳化硅光学镜面的光学加工过程各个步骤中所应用的磨具、磨料和加工方法。讨论了光学加工过程中各个步骤工艺参数的选择和降低碳化硅光学镜面表面粗糙度的途径。最后,简介了美国、俄罗斯和我国在碳化硅反射镜的光学加工方面所取得的成果。