TiO2纳米粒子增强的光纤损失模式共振折射率传感器

以多模光纤为基底来实现损失模式共振(LMR)折射率传感的灵敏度较低，在利用铟锡氧化物(ITO;In₂O₃和SnO₂的质量分数分别为90%和10%)激发光纤LMR传感的基础上，在ITO薄膜上静电组装二氧化钛(TiO₂)纳米粒子，实现折射率灵敏度的提升。使用Kretschman结构模型对传感器进行理论分析，仿真分析了LMR共振阶数与ITO薄膜厚度的关系，以及ITO作为LMR膜层实现折射率传感的可行性。通过在光纤侧壁磁控溅射ITO薄膜以产生LMR效应，制备ITO-LMR折射率传感器。通过折射率传感实验对ITO-LMR和TiO₂-ITO-LMR两种传感器进行性能测试，在1.3333～1.3840的折射率变化范围内，TiO₂-ITO-LMR传感器灵敏度可达1651.659 nm/RIU，相较于ITO-LMR折射率传感器，其灵敏度提升了3.058倍。     

平面光波导用于实时测试生化反应新方法的研究

在分析经典消逝波光波导生化传感器的基础上,为寻找性能更佳的传感器,探讨用更为直观的截止特性来进行生化传感。分别对三层及四层平板波导进行了研究,指出了作为基于截止特性的生化传感器三层波导结构存在的局限性。在理论上研究了可以在四层波导中使用变折射率材料来进行基于截止特性的生化传感,并给出了由空气隙、极化聚合物、高折射率薄膜、待测物组成的传感器结构示意图。用数值分析的方法绘出了此装置的灵敏度与高折射率薄膜厚度的关系曲线,并将它同经典消逝波光波导生化传感器灵敏度与薄膜厚度关系图进行了比较。结果表明,这种新型传感器理论上可以在较厚的薄膜结构中达到很高的灵敏度。     

基于多层石墨烯材料的光纤声波传感器

研究了一种基于多层石墨烯材料的光纤声波传感器,该传感器是由单模光纤和多层石墨烯薄膜构成的光纤法布里-珀罗干涉腔结构。分别采用多层的石墨烯和氧化石墨烯(GO)材料作为声压敏感薄膜,进行声波传感实验研究。结果表明,在音频范围内,基于石墨烯和GO薄膜的光纤声波传感器的平均信噪比分别达到56dB和69dB,平均最小可探测声压灵敏度分别为20.8μPa·Hz~(-1/2)和6.63μPa·Hz~(-1/2),远低于电学声波传感器的最小可探测声压灵敏度。基于石墨烯材料的光纤声波传感器具有更高的声波检测灵敏度,适用于强电磁干扰、狭小空间等环境下的微声压测量。     

基于表面等离子体共振和定向耦合的光子晶体光纤传感器

设计了一种具有较大动态检测范围的新型光子晶体光纤折射率传感器。光子晶体光纤中一个空气孔镀上金纳米薄膜作为表面等离子体共振传感通道用来检测低于石英基底材料的液体折射率,一个空气孔填充待测液体作为定向耦合器通道用于检测高于石英基底材料的折射率。该传感器可以实现折射率为1.32~1.52范围内的检测,且具有较高的传感灵敏度。在各向异性的完美匹配层(PML)下利用全矢量有限元法(FEM)对该传感器特性进行了数值研究,结果表明:在1.32~1.44和1.46~1.52的折射率范围该折射率传感器灵敏度最高分别可达13500 nm/RIU和28700 nm/RIU,RIU为折射率单位。     

光纤SPR湿敏传感器及其共振光谱特性研究

提出并研制了基于光纤SPR传感探针的新型湿敏传感器。首先研究了光纤SPR传感探针对环境湿度变化的敏感特性,在此基础上提出在光纤SPR传感探针表面增覆不同厚度且具有水分子吸附功能的PVA薄膜来实现环境相对湿度的监测。研究结果表明,增覆双层PVA薄膜的光纤SPR传感探针在高湿区具有较好监测效果,其共振强度对应的相对湿度测量灵敏度达到1.59%/%RH,较光纤SPR探针呈现显著提高。而增覆单层PVA薄膜的光纤SPR传感探针在高湿区共振波长对应的相对湿度监测灵敏度达到2.411nm/%RH。此外所提出的新型光纤SPR湿敏探针在PVA薄膜失效后经过特殊工艺处理仍可重复镀膜使用。     

基于表面等离子体共振和定向耦合的D形光子晶体光纤折射率和温度传感器

利用光子晶体光纤结构的灵活性和性能的优越性, 设计了一种基于D形光子晶体光纤的折射率和温度传感器. 在D形光子晶体光纤表面抛磨并镀上金纳米薄膜, 作为表面等离子体共振传感通道用来测量液体折射率; 在包层的一个空气孔中填充温敏液体甲苯, 作为定向耦合通道实现对温度的测量. 进一步的数值计算发现, 基于定向耦合效应的温度传感和基于表面等离子体共振的折射率传感相互独立, D形光子晶体光纤同时进行折射率和温度传感检测. 在各向异性的完美匹配层边界条件下利用全矢量有限元法对该传感器特性进行了数值研究, 发现D形光子晶体光纤的空气孔直径决定了定向耦合吸收峰的中心波长和温度传感的灵敏度, 金薄膜的厚度和D形结构的抛磨深度仅影响表面等离子体共振峰的相对强度. 结果表明: 该传感器在-10–80 ℃的温度范围内具有11.6 nm/℃的温度灵敏度, 在1.34–1.44折射率范围内折射率灵敏度最高可达26000 nm/RIU.     

新型声表面波电流传感器*

将声表面波技术的快速响应特点与磁致伸缩薄膜的高磁敏特点相结合,可实现一种快速、高灵敏、稳定可靠的新型电流检测技术。传感器由双通道差分式振荡器与沉积在传感通道器件表面的声传播路径上的磁致伸缩薄膜组成。该文基于分层介质中声传播理论及磁致伸缩效应,对声表面波电流传感机理进行了分析,以实现对传感器结构的优化设计。实验研制了采用铁钴(FeCo)薄膜的声表面波电流传感器,测试结果表明,该传感器具有快速响应和高灵敏特点。为抑制磁致伸缩薄膜自身的剩磁效应所带来的高磁滞误差,采用的有效途径是将沉积的磁致伸缩薄膜进行图形化设计。实验结果表明,采用栅阵化FeCo薄膜结构的传感器表现出更高检测灵敏度、更好线性及更低的磁滞误差。     

光波导振荡场传感器

针对消逝场传感器的不足,提出了一种传感介质处于波导芯层,且以超高阶导模为探针的光波导振荡场传感器.由于其波导芯层处于功率密度极高的振荡场区域,而超高阶导模又具有对芯层参数极为灵敏的性质,因此这种新型传感器的灵敏度大大增强.实现了超越消逝场传感器灵敏度极限值几个量级的位移传感器.     

新型表面波电流传感器优化设计

本文对结合磁致伸缩效应的新型声表面波电流传感器进行优化设计。传感器采用80 MHz声表面波双通道延迟线型差分振荡器,并在传感通道SAW器件表面声传播路径上溅射磁致伸缩薄膜,利用薄膜材料在电流激发磁场作用产生的磁致伸缩效应引起声传播速度的变化,并以相应振荡器频率的变化来表征待测电流。通过对不同磁致伸缩材料(FeCo和FeNi)以及薄膜厚度的传感效应进行分析,用以为传感器的优化设计提供思路,并通过实验进行验证,实验结果显示,相对于FeCo而言,采用FeNi作为敏感材料的电流传感器具有良好的重现性、线性度以及较高的灵敏度。     

侧边抛磨单模光纤表面等离子体传感器的设计和优化

光纤表面等离子体共振传感器具有体积小、抗电磁干扰,可以实现在线实时远距离检测的优点。为提高传感器的性能,建立了侧边抛磨光纤表面等离子体共振传感的物理模型,分别研究了侧边抛磨光纤的剩余厚度、银膜层的厚度对传感器的灵敏度、共振峰的深度和半高全宽等的影响。结果表明：光纤剩余厚度越小,表面等离子体共振现象越强;随银膜层的厚度增大,共振峰的宽度变宽,而传感器的灵敏度呈现非单调变化。通过综合表面等离子体共振传感器的折射率传感灵敏度和共振峰半高全宽,提出了质量因数作为传感器的优化指标,并最终得到最优化的设计方案为光纤剩余厚度为66.5 μm,银膜的厚度为50 nm,此时质量因数达到98.67。     

Novel optical film sensor design based on p-polarized reflectance

A new scheme of optical film sensor is presented. The sensor is based on p-polarized reflectance, consisting of a sensing coated substrate, is easily optimized for maximum sensitivity in different applications. The resolutions of refractive index n_f, extinction coefficient k_f and thickness h_f of the sensitive films are predicted to be 10⁻⁷, 10⁻⁵ and 10⁻³ nm, respectively. Experimentally, we selected the sol–gel derived SnO₂ films as gas-sensitive films and conducted preliminary gas-sensing test. The results indicate that novel optical film sensor scheme has higher sensitivity, and the detection sensitivity is available to 10⁻¹ ppm on the condition of optimum optical parameters and incident angle.     

Optical fiber long-period grating with solgel coating for gas sensor

The novel long-period fiber grating (LPFG) film sensor is composed of the long-period grating coated with solgel-derived sensitive films. The characteristics of the transmissivity of the LPFG film sensor are studied. By analyzing the relation among the sensitivity Sn, the thin film optical parameters, and the fiber grating parameters, the optimal design parameters of the LPFG film sensor are obtained. Data simulation shows that the resolution of the refractive index of this LPFG film sensor is predicted to be 10(-8). Experimentally, a LPFG film sensor for detection of C(2)H(5)OH was fabricated, and a preliminary gas-sensing test was performed.     

ZnO thin film on side polished optical fiber for gas sensing applications

In this work, thin ZnO films have been produced by pulsed laser deposition on side-polished fiber for optical gas sensor applications. The influence was investigated of the processing parameters, such as substrate temperature and oxygen pressure applied during deposition, on the sensitivity to ammonia of the sensing element. A shift of the spectral position of the resonance minimum to the longer wavelengths was observed at room temperature for the sample prepared at 150 °C substrate temperature and 20 Pa oxygen pressure. Spectral changes in the range 0.16-1.13 nm for NH₃ concentrations between 500 and 5000 ppm were also observed.     

长周期光纤光栅气敏薄膜传感器结构优化

基于三包层长周期光纤光栅模型,研究了包层表面涂覆一层溶胶凝胶气敏薄膜的长周期光纤光栅化学传感器的灵敏度Sn与薄膜光学参量(折射率n3和厚度h3)和光纤光栅结构参量(光栅周期、折变量和光栅长度)之间的关系。采用最优化数值方法,找到了获得高灵敏度所需的最佳膜层光学参量和光栅结构参量。理论计算表明,该类型传感器对膜层折射率的测量分辨率高达10-8。实验上制作了对乙醇气体敏感的传感器,并证实了传感器结构优化的必要性。     

基于光纤微结构加工和敏感材料物理融合的光纤传感技术

将功能敏感材料与光纤在物理层面进行有机融合,充分发挥光纤传感器在结构集成、材料集成等方面的优势,将有望发展新型的光纤传感器件和系统.本文综述了飞秒激光光纤微加工技术分别在标准的单模光纤和光纤光栅上制备微结构,再结合敏感材料制备技术,实现在物理层面上光纤传感器材料和结构的集成和融合,探索实现新型高性能的光纤传感新技术.     

Performances of different metals in optical fibre-based surface plasmon resonance sensor

The capability of various metals used in optical fibre-based surface plasmon resonance (SPR) sensing is studied theoretically. Four metals, gold (Au), silver (Ag), copper (Cu) and aluminium (Al) are considered for the present study. The performance of the optical fibre-based SPR sensor with four different metals is obtained numerically and compared in detail. The performance of optical fibre-based SPR sensor has been analysed in terms of sensitivity, signal-to-noise (SNR) ratio and quality parameter. It is found that the performance of optical fibre-based SPR sensor with Au metal is better than that of the other three metals. The sensitivity of the optical fibre-based SPR sensor with 50 nm thick and 10 mm long Au metal film of exposed sensing region is 2.373 μm/RIU with good linearity, SNR is 0.724 and quality parameter is 48.281 RIU^− 1. The thickness of the metal film and the length of the exposed sensing region of the optical fibre-based SPR sensor for each metal are also optimized.     

Finite element simulation of Love wave sensor for the detection of volatile organic gases

The three-dimensional (3D) finite element (FE) simulation and analysis of Love wave sensors based on polyisobutylene (PIB) layers/SiO$_{2}$/ST-90$^\circ$X quartz structure are presented in this paper, as well as the investigation of coupled resonance effect on the acoustic properties of the devices. The mass sensitivity of the basic Love wave device with SiO$_{2}$ guiding layers is solved analytically. And the highest mass sensitivity of 128 m$^{2}$/kg is obtained as $h_{\rm s}/\lambda =0.175$. The sensitivity of the Love wave sensors for sensing volatile organic compounds (VOCs) is greatly improved due to the presence of coupled resonance induced by the PIB nanorods on the device surface. The frequency shifts of the sensor corresponding to CH$_{2}$Cl$_{2}$, CHCl$_{3}$, CCl$_{4}$, C$_{2}$Cl$_{4}$, CH$_{3}$Cl and C$_{2}$HCl$_{3}$ with the concentration of 100 ppm are 1.431 kHz, 5.507 kHz, 13.437 kHz, 85.948 kHz, 0.127 kHz and 17.879 kHz, respectively. The viscoelasticity influence of the sensitive material on the characteristics of SAW sensors is also studied. By taking account of the viscoelasticity of the PIB layers, the sensitivities of the SAW sensors with the PIB film and PIB nanorods decay in different degree. The gas sensing property of the Love wave sensor with PIB nanorods is superior to that of the PIB films. Meanwhile, the Love wave sensors with PIB sensitive layers show good selectivity to C$_{2}$Cl$_{4}$, making it an ideal selection for gas sensing applications.     

Characterization and sensing property studies of the Pt | Nafion electrode prepared by the chemical reduction method

A novel electrochemical hydrogen sensor which consists of a solid electrolyte polymer (SEP) and catalytic active electrode operating at room temperature was fabricated and investigated. Nafion is utilized as polymer proton conducting membrane onto which a catalytic electrode was deposited by anin-situ impregnation reduction (I-R) technique. In this work, Pt was selected as active catalyst for hydrogen oxidation and the deposition conditions were modified to optimise the parameters for application in hydrogen sensors and to improve the metal utilization so that the electrode loading could be reduced without loss of electrochemical performance. The hydrogen sensing characteristics with air as reference gas are reported. A maximum sensitivity of about 0.01 μA cm⁻² ppm⁻¹ was obtained. The response time was observed to be in the range of 10–50 seconds. The experimental results show that long term sensor stability exists at room temperature. The thin Pt films were characterized by XRD, infrared spectroscopy, optical microscopy, scanning electron microscopy and EDAX. Paper presented at the Patras Conference on Solid State Ionics — Transport Properties, Patras, Greece, Sept. 14–18, 2004.     

螺旋形塑料光纤表面等离子体共振折射率传感器

研究了基于波长调制的螺旋形塑料光纤(plastic optical fiber, POF)表面等离子体共振(surface plasmon resonance, SPR)折射率传感器。采用机械热压和扭曲法将塑料光纤制备成螺旋形,在螺旋形POF上通过磁控溅射蒸镀一定厚度(约50 nm)的金属薄膜来激励SPR效应,从而形成螺旋形POF-SPR传感器。通过对螺旋形POF-SPR传感器的结构进行修饰,研究不同结构参数对折射率传感特性的影响。实验结果表明:由厚度为500μm扁平形POF扭制、螺纹数为4的螺旋形POF-SPR传感器具有较好的线性度和折射率传感特性,在折射率为1.335～1.400范围内测得的灵敏度为1 262 nm/RIU。该传感器具有成本较低、制备简单、结构稳定等优点。     

非晶钛酸锶钡薄膜的金属有机分解法制备及其光学性能

本文采用2-辛酸钡(Ba(C₈H₁₅O₂)₂)和3-甲基丁基醋酸盐(CH₃COOC₂H₄CH(CH₃)₂-)为基的特殊前驱体溶液,在硅和石英基片上低温制备Ba_0.7Sr_0.3TiO₃ (BST0.7)薄膜.性能测试结果表明,厚度约为214 nm的非晶BST0.7薄膜的光学带隙能和折射率分别为4.27 eV和n=1.94.薄膜在可见光和近红外区域的消光系数远远低于多晶BST薄膜,约为10^-3数量级.激发波长为450 nm时,在室温环境下非晶BST0.7薄膜在波长520—610 nm处发出强烈的可见光,峰值为540—570 nm,而结晶态的BST0.7薄膜则无发光现象. 关键词： 钛酸锶钡 非晶薄膜 金属有机分解法 光学性能