费米折射率平面波导激励的差分检测型对称结构表面等离子共振传感研究

为了实现被测折射率范围可调,提高检测灵敏度,将双波长差分检测技术应用于平面波导激励的金属-介质-金属组成的对称型表面等离子体共振传感结构中.通过对对称结构的模式特性分析,研究了该结构中激发等离子体表面波时,介质厚度与被测折射率的关系及双波长差分检测的原理.采用离子交换法制备平面波导,用费米函数拟合其渐变折射率分布.用光强调制方式,分别进行单波长和双波长差分检测,对折射率为1.33~1.428之间的甘油溶液进行测试,实验结果表明,该结构可激发等离子体表面波,与传统平面波导激励的表面等离子体共振传感结构相比,通过改变被测介质的厚度可以改变共振条件,进而改变折射率的测量范围.若被测范围选择合适,检测的线性较好,采用差分检测方法比单波长检测方法的灵敏度提高近一倍.     

光强检测型空芯光纤表面等离子体共振传感器EI北大核心CSCD

提出了基于光强检测方式的空芯光纤表面等离子体共振(SPR)传感器。采用波长为532nm的激光作为光源,对所设计传感器的性能进行了研究,并采用光传输模型对传感器的性能进行了理论分析,所得理论结果与实验结果相符。传感器在线性区的最高灵敏度和最佳分辨率分别达到8380.3μW/RIU和5.5×10^(-6) RIU。相比于波长检测型空芯光纤SPR传感器,所提传感器的分辨率提高了2个数量级,且实验系统简单,有利于器件的进一步小型化。     

表面等离子体共振传感技术应用于小分子检测

人体内的生物小分子对维持生命体健康具有重要影响,此类分子参与生命体的血液循环及免疫系统,因此检测生命体中生物小分子对研究小分子在生命体中的生理功能有着重要的意义.傅里叶变换-表面等离子体共振(Fourier transform-surface plasmon resonance,FT-SPR)光谱技术具有操作简便、灵敏...     

聚合物波导型表面等离子体共振传感器的特性研究

基于表面等离子体共振理论,将SU-8作为波导芯层材料,以聚甲基丙烯酸甲酯(PMMA)为下包层材料,设计了一款聚合物波导型SPR传感器。理论计算了波导芯层折射率、被测物折射率、不同金属薄膜及其厚度等因素对表面等离子体共振曲线的影响。分析结果表明,在可测试范围内,被测物折射率越大,灵敏度越高;波导芯层折射率减小,共振峰向长波方向移动,被测物检测范围整体向折射率小的方向偏移,波导芯层折射率增大则相反。     

反射式光纤表面等离子体波共振传感器特性研究

研究了一种基于表面等离子体波共振(SPR)光谱分析的折射率检测新方法。研究发现,表面等离子体波共振效应光谱特征的折射率灵敏度会随着液体性质变化而发生改变。根据折射率测量范围不同,分别选择共振波长和共振强度作为检测参量,实现理论折射率分辨力达到10~(-5)数量级以上。在理论分析和实验基础上,设计出一种基于共振光强检测的终端反射式光纤表面等离子体波共振效应传感系统,采用将传感信号和基准光信号的比值作为液体折射率变化的度量值。在1．3325～1．3991的折射率测量范围内,度量值与折射率之间呈现单调递减关系,线性相关系数为0．9983。通过定义耦合系数,还可实现对表面等离子体波共振效应效应强弱和变化趋势的评估。     

基于银/二氧化钛复合膜的表面等离子共振气体传感器

表面等离子体共振是一种免标记的传感技术,当介质周围的介电常数发生改变时,则SPR谐振光谱特性也会随之改变.因此表面等离子体共振传感技术已广泛应用于生物化学和环境监测等领域.由于二氧化钛(TiO2)覆盖层不仅可以保护金属层,还能调谐SPR谐振的光谱强度和谐振波长于近红外波段,应用于1550 nm的光纤传感,其氧化还原反应...     

基于2S2G棱镜的新型反向表面等离子共振生物传感器

提出了一种基于反向表面等离子体共振原理,由Ge_(20)Ga_5Sb_(10)S_(65)-钯-石墨烯分子-生物分子四层结构构成的新型生物传感器。当生物分子之间发生相互作用时,引起生物分子层折射率的变化,从而导致反向表面等离子体共振角的偏移。在此基础上,根据传输矩阵法推导了传感器的输出光谱,重点讨论了本文提出的传感器与传统传感器相比,在灵敏度、分辨率、动态检测范围以及检测信号信噪比方面取得的进展。另外,通过对比研究,深入分析了辅助介质层石墨烯厚度对传感器性能的影响。最后,利用近红外光作为提出的传感器的入射光,分析了在近红外区域传感器性能的改善。研究结果表明:单层石墨烯分子使传感器性能达到最佳;反向表面等离子共振峰强度约为入射光强的80%~90%,使传感器的输出信号具有较大的信噪比;在可见光区域,当入射光波长为632.8nm时,提出的反向表面等离子共振生物传感器的分辨率是基于SiO_2棱镜耦合反向表面等离子共振生物传感器的1.9倍,是传统表面等离子共振生物传感器的3.5倍,提出的传感器的动态检测范围约是现有传感器的2倍;利用Ge_(20)Ga_5Sb_(10)S_(65)棱镜可使反向表面等离子共振生物传感器检测光波长由可见光区域扩展到近红外区域,当入射光为1 000nm时,传感器的分辨率是可见光区域的3~4倍。该研究对基于反向表面等离子体共振原理生物传感器的实现与发展具有重要意义。     

基于表面等离子体共振的新型超宽带微结构光纤传感器研究

基于表面等离子体共振的微结构光纤传感器具有高灵敏、免标记和实时监控等优点.如今,由于此类传感器广泛应用于食品安全控制、环境检测、生物分子分析物检测等诸多领域而受到大量研究.然而,目前所报道的绝大多数此类传感器只能应用于可见光或近中红外传感.因此,对可应用于中红外传感的表面等离子体共振微结构光纤传感器的研究是一项极具挑战...     

表面等离子体共振与表面增强拉曼散射相关性研究

本实验利用实验室搭建的SPR-SERS显微拉曼光谱仪同时检测了吸附在40 nm银膜上的4-amin-othiophenol(4-ATP)自组装膜的表面等离子体共振(Surface Plasmon Resonance,简称SPR)消光谱及表面增强拉曼散射(Surface-Enhanced Raman Scattering,简称SERS)光谱,研究了两者之间的相关性。实验发现随着SPR吸收的增强,SERS强度也急剧增强,在SPR共振角附近SERS强度是远离共振角处的20多倍。因此在共振角附近能够极大的提高SERS的检测灵敏度并扩展SERS的应用。     

用表面等离子体共振传感器检测纳米间距

结合物理光学原理和表面等离子体共振（SPR）角度传感器,提出了可以突破衍射极限的纳米间距检测方法。在理论上建立起纳米间距和位相改变量之间的函数关系,借助于SPR角度传感器的高灵敏性,提出通过检测出射光束振动方向的p分量和s分量的位相差值来实现纳米间距的实时检测。模拟结果显示：纳米间距改变量从-0.5～0.5μm变化时,位相改变量可实现-150°～150°的变化,检测灵敏度〉1 nm。该检测方法能够实现10 nm以下间距的灵敏检测,且具有结构简单,易于操作,实时检测的特点。     

LED based fiber optic surface plasmon resonance sensor

Modeling of a miniaturized fiber optic sensor based on surface plasmon resonance utilizing a broad band diffuse source is presented. Attenuated total internal reflection with Kretschmann configuration is the basis of the theoretical model. For simulation both meridional and skew rays are considered. The performance of the sensor is evaluated in terms of sensitivity, detection accuracy and signal to noise ratio. Effects of the numerical aperture of the fiber, core diameter and length of the sensing region on the performance parameters of the sensor are studied. The results are obtained for gold and silver metallic layer on the core of the fiber. The theoretical results obtained are compared with SPR based fiber optic sensor utilizing focused beam on the end face of the fiber from a collimated source. The advantages of using broadband LED (diffuse source) source for launching light in the fiber are the miniaturization, compactness and low cost of the sensor.     

基于计算机软件的新型SPR传感器设计

为了改进SPR传感器灵敏度低、稳定性差、测量范围窄等问题,基于光的衰减全反射理论设计了一种SPR传感装置。利用FDTD计算机软件分析得到:设计的结构分子层和金属薄膜之间的界面磁场强度得到极大地提高,测量精度有了显著的改进;很大一部分倏逝场能量集中在表面等离子共振区,倏逝波的强度非常强。     

High-resolution surface plasmon resonance sensor based on linewidth-optimized nanohole array transmittance

A high spectral resolution, 2D nanohole-array-based surface plasmon resonance sensor that operates at normal or near normal incidence--facilitating high spatial resolution imaging--is presented. The angular and spectral transmittance of the structure is modified from a Fano type to a pure Lorentzian line shape with a parallel and orthogonal polarizer-analyzer pair. This change leads to a linewidth narrowing that maximizes the sensor resolution, which we show to be of O(10(-5)) refractive index units (RIU). We estimate the potential of this system of O(10(-6)) RIU under optimal conditions.     

Fiber optic sensor based on surface plasmon resonance with nanoparticle films

This paper reports on a novel design of a fiber optic surface plasmon resonance (SPR) sensor based on nanoparticle metal film. The performance of the proposed sensor in terms of its signal-to-noise ratio (SNR) and sensitivity under different conditions related to the film with spherical gold nanoparticles embedded in a host material is theoretically analyzed. In particular, the effect of the parameters such as gold particle size, film thickness, and refractive index of host material is studied and the possible explanation, whenever required, is given. The numerical results presented in this paper leads to fulfill the requirement of significant optimization of the important design parameters to achieve a high SNR and sensitivity of a fiber optic SPR sensor with nanoparticle films.     

Contributions to a reliable hydrogen sensor based on surface plasmon surface resonance spectroscopy

Hydrogen is being seen as a potentially inexhaustible, clean power supply. Direct hydrogen production and storage techniques that would eliminate carbon by-products and compete in cost are accelerated in R&D due to the recent sharp price increase of crude oil. But hydrogen is also linked with certain risks of use, namely the danger of explosions if mixed with air due to the very low energy needed for ignition and the possibility to diminish the ozone layer by undetected leaks. To reduce those risks efficient, sensitive and very early warning systems are needed. This paper will contribute to this challenge in adopting the optical method of Surface-Plasmon-Resonance (SPR) Spectroscopy for a sensitive detection of hydrogen concentrations well below the lower explosion limit. The technique of SPR performed with fiberoptics would in principle allow a remote control without any electrical contacts in the potential explosion zone. A thin palladium metal layer has been studied as sensing element. A simulation programme to find an optimum sensor design lead to the conclusion that an Otto-configuration is more advantageous under intended “real world” measurement conditions than a Kretschmann configuration. This could be experimentally verified. The very small air gap in the Otto-configuration could be successfully replaced by a several hundred nm thick intermediate layer of MgF₂ or SiO₂ to ease the fabrication of hydrogen sensor-chips based on glass slide substrates. It could be demonstrated that by a separate detection of the TM- and TE-polarized light fractions the TE-polarized beam could be used as a reference signal, since the TE-part does not excite surface plasmons and thus is not influenced by the presence of hydrogen. Choosing the measured TM/TE intensity ratio as the analytical signal a sensor-chip made from a BK7 glass slide with a 425 nm thick intermediate layer of SiO₂ and a sensing layer of 50 nm Pd on top allowed a drift-free, reliable and reversible determination of hydrogen concentrations up to about 10 vol.% in dry or humid air with a detection limit of 0.04 vol.% with response times of around 2 min.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

表面等离子体波传感器角度敏感特性的研究

研究了表面等离子体波共振(SPR)光谱对入射光角度变化的敏感特性,提出了对共振波长和共振强度进行双参数检测的方法。理论分析和实验表明,共振波长和共振强度同时对入射角度的微小改变非常敏感,且相互之间具有良好的对应关系。通过选择合适的棱镜、金属薄膜、调制层等结构参数,能有效地调整角度敏感的范围和灵敏度。     

Cross-point analysis for a multimode fiber sensor based on surface plasmon resonance

A novel analysis based on surface plasmon resonance (SPR) with a side-polished multimode fiber and a white-light (halogen light) source is presented. The sensing system is a multimode optical fiber in which half of the core has been polished away and a 40 nm gold layer is deposited on to the polished surface by dc sputter. The SPR dip in the optical spectrum is investigated with an optical spectrum analyzer (OSA). In our SPR fiber sensor, the use of liquids with different refractive indices leads to a shift in the spectral dip in the SPR curve. The cross point (CP) of the two SPR spectra obtained from the refractive-index liquid and the deionized water measurements was observed with the OSA. The CP is shifted sensitively in wavelength from 630 to 1300 nm relative to a change in the refractive index of the liquid from 1.34 to 1.46. High sensitivities of 1.9 x 10(-6) refractive-index units (RIUs) in the range of the refractive index of the liquid from 1.40 to 1.44 of 5.7 x 10(-7) RIUs above the value of 1.44 are proposed and demonstrated in our novel SPR analysis.