基于表面等离子体共振的双芯光子晶体光纤横向应力传感器EI北大核心CSCD

基于表面等离子体共振(SPR)效应,设计了一种采用双芯结构光子晶体光纤(PCF)作为光波导的横向应力传感器。通过建立SPR耦合波模型和PCF结构的形变模型,利用全矢量有限元法进行数值模拟,获得了基模共振峰的偏移量与横向应力的关系。结果表明共振峰波长的偏移量与所施加应力具有很好的线性关系。对PCF的截面结构进行优化设计,通过选择适当的空气孔层数、直径和周期,可获得较高的测量灵敏度。该研究可为基于SPR的PCF横向应力传感器的设计提供理论依据。     

基于双芯光子晶体光纤的中红外表面等离子体共振低折射率传感器

为了在中红外区域实现气凝胶、七氟醚(麻醉剂重要成分)等物质的折射率检测,拓展折射率检测范围,提出了一种基于双芯光子晶体光纤的表面等离子体共振低折射率传感器.光子晶体光纤由两种大小不同的空气孔围绕中心气孔构成,通过对光纤抛磨,最外侧大空气孔直接与待测物质接触,实现基于金属外涂覆的折射率实时测量.采用全矢量有限元法对该传感器的理论模型进行分析,结果表明,在1.12～1.37折射率范围内,传感器的共振波长位于中红外区域2 505～3 181nm,最高灵敏度为12 000nm/RIU,分辨率为8.33×10-6.该传感器利用中红外波段实现了低折射率检测,并且获得了超宽的检测范围和较高的灵敏度,在化工检测、生物医学传感以及水环境监测等领域具有广泛的应用前景.     

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。     

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...     

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。     

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。     

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.     

基于表面等离子体共振的光子准晶体光纤甲烷氢气传感器（英文）

设计了一种用于同时检测甲烷和氢气的基于表面等离子体共振(SPR)的新型光子准晶体光纤(PQF)传感器。在该传感器中,在银膜上分别沉积Pd-WO3和掺杂聚硅氧烷的笼型分子E薄膜作为氢气和甲烷的敏感材料。采用全矢量有限元方法对PQF-SPR传感器进行数值分析,结果证明该传感器具有良好的传感性能。在0%～3.5%的浓度范围内,氢气的最大检测灵敏度和平均灵敏度分别为0.8 nm/%和0.65 nm/%,甲烷的最大灵敏度和平均灵敏度分别为10 nm/%和8.81 nm/%。该传感器具有同时检测多种气体的能力,在设备小型化和远程监测方面具有很大的潜力。     

基于表面等离子体共振原理的空芯光纤传感器

设计了一种基于表面等离子体共振原理,使用空芯光纤作为光波导、外表面镀金属膜的光学材料圆柱体作为探头的新型折射率传感器。通过建立光学模型进行分析,在理论上推导出了这种传感器的传输光谱损耗公式,并针对该传感器在不同的光纤长度、探头材料、检测物质折射率等参数设置下的检测性能进行了分析,获得了各种参数对其性能的影响。由于该传感器可针对不同折射率的检测物质灵活地更换合适探头材料,相对于传统的表面等离子体共振光纤传感器,在易用性和性价比等方面具有更好的应用价值。     

基于氮化钛薄膜表面等离子体共振特性的双芯光子晶体光纤温度传感器

提出一种基于表面等离子体共振的双芯光子晶体光纤温度传感器,其中双芯光子晶体光纤为折射率导光型,其中心圆孔表面镀氮化钛薄膜,内部填充具有较大热敏系数的乙醇和氯仿的混合液体,其纤芯模与表面等离子体激元耦合的共振波长偏移可反映液体混合物的温度或折射率.利用全矢量有限元法分析了不同因素对传输损耗谱及其共振波长的影响.仿真结果表明:外包层空气孔直径增大,以及最内层包层空气孔直径和空气孔间距减小可以提高耦合效率,从而增强共振峰.对比分析发现在-20℃～120℃温度范围内,氮化钛薄膜比传统金膜表现出更好的等离子传感特性,随着膜厚增加,其共振波长偏移量增加,温度灵敏度提高,灵敏度最高可以达到6.22 nm/K.     

基于D型双芯PCF的近红外宽检测范围SPR折射率传感器

现有报道的PCF-SPR折射率传感器的检测范围普遍较窄,不能实现低折射率的检测,且工作波段多数集中在可见光或通信波段,这限制了传感器的应用范围.鉴于此,提出了一种基于D型双芯PCF结构的SPR传感器,使用氧化铟锡作为等离子体材料沉积在D型PCF抛光表面,并对该传感器的理论模型进行了分析,包括金属参数对传感性能的影响,P...     

Surface plasmon resonance based fiber optic sensor utilizing indium oxide

A highly sensitive surface plasmon resonance (SPR) based fiber optic sensor with indium oxide (In₂O₃) layer coated on the core of the optical fiber is presented and theoretically analyzed. The sensitivity of the SPR based fiber optic sensor has been evaluated numerically. It is shown that the proposed SPR based fiber optic sensor with In₂O₃ layer possesses high sensitivity in the near infrared region of spectrum, which needs attention to many environmental and security applications and offers more accurate and highly reproducible measurements. In addition, the sensitivity of the SPR based fiber optic sensor decreases with the increase in the thickness of In₂O₃ layer. With sensitivity as high as 4600 nm/RIU, the 170 nm thick In₂O₃ layer based fiber optic SPR sensor demonstrates better performance.     

Surface plasmon resonance based tapered fiber optic sensor with different taper profiles

A theoretical model for surface plasmon resonance (SPR) based tapered fiber optic sensor is proposed with three different taper profiles, namely, linear, parabolic, and exponential-linear. The effect of taper ratio and taper profiles on the sensor’s performance is studied in detail and the design considerations for significantly enhanced sensitivity are reported. The study shows that the exponential-linear taper profile with high taper ratio provides the best performance. The physical reasons behind sensitivity enhancement due to taper ratio and taper profile are given, wherever required.     

Surface plasmon resonance device with imaging processing detector for refractive index measurements

This work presents a new surface plasmon resonance (SPR) instrument based on Kretschmann configuration. This device acquires and processes the reflected SPR image of the sample by using a webcam together with an image processing algorithm that transforms the RGB image in numeric values and correlates the integrated intensity with the refractive index of the solution. Experimental signals were compared with theoretical values and it was found an excellent agreement. In addition, the applicability of the instrument was tested by measuring the refractive index of solutions in a continuous flow mode. Excellent stability and sensitivity of the signal were found in the presence of small changes of the refractive index.     

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.     

Surface plasmon resonance sensors based on Ag-metalized nanolayer in microstructured optical fibers

Surface plasmon resonance sensors based on Ag-metalized nanolayer in microstructured optical fibers are theoretically analyzed by using finite element method (FEM). In our simulations we use Drude-Lorentz model to describe the metal dielectric constant. The numerical results show that the sensitivity of Ag-metalized SPR sensor could reach 1167 nm/RIU and corresponding resolution is 8.57×10⁻⁵ RIU. Compared to conventional Au-metalized SPR sensors the performance of our device is obviously better.     

基于少模-无芯-少模光纤结构的高灵敏度折射率传感器

光纤折射率传感器广泛应用于各种复杂环境的监测。设计了一种基于少模光纤（fewmode fiber,FMF）–无芯光纤（coreless fiber,CLF）–FMF结构的高灵敏度折射率传感器。该传感器由2小段FMF之间熔接1段减薄的CLF组成马赫-增德尔干涉仪（Mach–Zehnder interference,MZI）,测量外界折射率,利用光纤布拉格光栅（fiber Bragg grating,FBG）进行温度补偿。MZI干涉光谱中的谐振波谷同时受折射率和温度影响,FBG只受温度的影响。利用MZI和FBG的折射率和温度灵敏度系数构建灵敏度矩阵,实现折射率和温度的同步测量。实验结果表明,MZI折射率灵敏度为345.66 nm/RIU,温度灵敏度为0.013 4 nm/℃;FBG的温度灵敏度为0.010 4 nm/℃。     

Refractive index sensor based on high-order surface plasmon resonance in gold nanofilm coated photonic crystal fiber

We propose a novel kind of wide-range refractive index optical sensor based on photonic crystal fiber(PCF) covered with nano-ring gold film.The refractive index sensing performance of the PCF sensor is analyzed and simulated by the finite element method(FEM).The refractive index liquid is infiltrated into the cladding air hole of the PCF.By comparing the sensing performance of two kinds of photonic crystal fiber structures, a wide range and high sensitivity structure is optimized.The surface plasmon resonance(SPR) excitation material is chose as gold, and large gold nanorings are embedded around the first cladding air hole of the PCF.The higher order surface plasmon modes are generated in this designed optical fiber structure.The resonance coupling between the fundamental mode and the 5 th order surface plasmon polariton(SPP)modes is excited when the phase matching condition is matched.Therefore, the 3 rd loss peaks appear obvious red-shift with the increase of the analyte refractive index, which shows a remarkable polynomial fitting law.The fitnesses of two structures are 0.99 and 0.98, respectively.When the range of refractive indices is from 1.40 to 1.43, the two kinds of sensors have high linear sensitivities of 1604 nm/RIU and 3978 nm/RIU, respectively.