光波导生物化学传感器研究进展

光波导具有结构简单,体积小,耐腐蚀,电绝缘性好,便于集成等特点.光波导对折射率、吸收以及放光过程（例如：化学发光或荧光）的变化敏感.这些变化对波导中传输的光起到了调制作用,可利用光波导的这些特性制成各类传感器.其中光波导生物化学传感器是将光波导技术与化学、生物工程技术相结合,它必将会在生物化学领域中发挥重要作用.本文综述了已经研制出的几种类型的光波导生物传感器,并对其特性进行了比较.     

集成光波导传感器的研究进展

集成光波导传感器是光纤传感器的有利补允,以其灵敏度高、不受外部电磁场干扰等优点吸引了科研工作者的注意。阐述了集成光波导传感器的原理、种类、应用及研究进展。     

基于光子晶体波导的折射率传感器的灵敏度优化设计

通过研究波导两侧缺陷处的折射率对二维光子晶体波导透射光谱的影响,提出一种提高折射率传感器灵敏度的方案。计算结果表明光子透射带上边沿的偏移量与传感区折射率的大小存在一定关系,在相同的折射率变化量下通过改变波导两侧缺陷处圆孔的相关几何参数可极大提高光子透射带上边沿的偏移量,即提高折射率传感器的灵敏度。通过优化设计,传感器的灵敏度由折射率变化区间0.0~1.0的55 nm/RIU(RIU表示折射率单元)与1.1~2.0的36 nm/RIU分别提高到对应的405 nm/RIU以及222 nm/RIU。     

Use of Reversal Nanoimprinting of Nanoparticles to Prepare Flexible Waveguide Sensors Exhibiting Enhanced Scattering of the Surface Plasmon Resonance

A flexible surface plasmon resonance (SPR)‐based scattering waveguide sensor is prepared by directly imprinting hollow gold nanoparticles (NPs) and solid gold NPs onto flexible polycarbonate (PC) plates—without any surface modification—using a modified reversal nanoimprint lithography technology. Controlling the imprinting conditions, including temperature and pressure, allows for the fine adjustment of the depths of the embedded metal NPs and their SPR properties. This patterning approach exhibits a resolution down to the submicrometer level. A 3D finite‐difference time domain simulation is used to examine the optical behavior of light propagating parallel to the air/substrate interface within the near‐field regime. Consistent with the simulations, almost an order of magnitude enhancement in the scattering signal after transferring the metal NPs from the glass mold to the PC substrate is obtained experimentally. The enhanced signal is attributed to the particles' strong scattering of the guiding‐mode waves (within the waveguide) and the evanescent wave (above the waveguide) simultaneously. Finally, the imprinting conditions are optimized to obtain a strongly scattering bio/chemical waveguide sensor.     

Buried-oxide silicon-on-insulator structures. II. Waveguide gratingcouplers

For pt.I, see ibid., vol.28, no.1, p.157-63 (1992). Grating couplers formed in buried-oxide silicon-on-insulator structures are analyzed using both a convergent Block wave approach and a simple approximate method. Strong interface reflections that occur during grating coupling can cause interference effects which result in variations in coupling efficiency and coupling length by an order of magnitude when varying grating period and film thickness parameters. Results indicate that proper coupler design is essential in order to obtain efficient coupling     

Realization of Tapered Waveguide by Stretching the Rod Waveguide

By stretching the rod waveguide with different velocities in opposite directions, the tapered waveguide can be fabricated. In condition of taking no account of volume expansion caused by heating and under the assumptions of volume conservation,the rod waveguide can be stretched freely in the heated region without being stretched outside of the heated region. A model,which shows the relation of the transition shape and the two factors, that is the ratio of two velocity and the heated region length, is presented for the shape of the taper transition through mathematic deduction. Based on this model, a desired tapered waveguide can be fabricated. The tapered waveguide are widely used for fabricating tapered fiber couplers and sensors. In addition, the conclusion can be used for fabricating fused fiber coupler.     

传感器

能滤除假回波的超声液位计；能测量多种气体的瞬态分析仪；通孔式加速度计；法兰安装式扭矩变送器；基于微处理器的指示器／调节器。     

传感器

硫化氯分析仪;防堵塞型液位计;区域视觉传感器;带数字编程功能的超声传感器;基于USB接口的倾角传感器。[编者按]     

传感器

不含聚氯乙烯的温度传感器M3000系列温度传感器采用不含聚氯乙烯的电缆,此电缆不含卤化物及对环境有害的增塑剂或含有重金属的稳定剂。此新款温度传感器延续了其前身产品M2000系列的成功,在温度循环试验中,     

传感器

连续式液位传感器UCL-520系列UCL-520型系列连续式超声波水位传感器可用于处理非接触式应用,例如工业水处理、废水管理以及化学制品储存。使用两线超声波变送器,提供高达8m的量距,这些传感器集成了坚固的PVDF换能器,可用于超纯、腐蚀性或     

传感器

霍尔效应传感器开关AH1802和AH1888低压全极性元件可在宽泛的电源电压下工作,并支持从单节锂离子电池到两节碱性/锌电池的多种电池配置。以AH1888为例,其     

传感器

热能管理传感器LM95172Q是一款可监控汽车电子系统温度的数字温度传感器,该产品的温度监控范围可高达175℃,并且可在130～160℃的范围内保持±1℃的精确度。LM95172Q传感器在高温环境下仍可保持高精确度,进一步调低系统防护带的水平让系统设计工程师可以开发性     

传感器

采用增强型像素结构的CMOS图像传感器;可用在极恶劣环境下的不锈钢视觉传感器;全集成200万像素CMOS图像传感器.     

传感器

XBee无线电池传感器,基于MEMS的振动传感器,显示设备亮度控制光感应器.     

传感器

小型化数字环境亮度传感器;具有±4g测量范围的MEMS传感器。     

矩形波导到圆波导模式变换器的优化设计

在圆形槽波导微波毫米波器件中,常遇到矩形一圆形槽波导的模式变换问题,而矩形一圆波导模式变换是矩形一圆形槽波导模式变换的重要组成部分。本文应用有限元方法,首先由分析N端口波导结问题过渡到两端口的矩形一圆波导模式变换器,然后针对现有模式变换器的圆端口面的电场极化方向倾斜的问题利用加圆波导段的方法进行了优化,并设计了一个新的反射微小,结构紧凑和电场极化方向竖直的矩形一圆波导模式变换器．计算结果满足了设计要求。     

Waveguide nanoelectronics

A theoretical study is presented concerning the electron transport in waveguides of nonuniform cross section that can be formed by nanolithography in a two-dimensional electron gas, with waveguide constrictions and dilatations behaving like potential barriers and quantum wells, respectively, in semiconductor heterostructures. The problem is treated in the multimode approximation. It is found that strong mode coupling makes Fano resonances a major contributor to the current-voltage characteristic, together with over-barrier resonances and resonant tunneling.     

传感器

小型化激光导航传感器；工业标准的高精度数字温度传感器系列；