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（英文）

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.对比分析发现在一20℃~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.     

基于侧边抛磨光纤表面等离子体共振的折射率和温度传感研究

用轮式侧边抛磨法制作侧边抛磨光纤,通过磁控溅射法溅射金膜制成侧边抛磨光纤表面等离子体共振(SPR)传感器,并通过理论和实验对传感器的折射率灵敏度以及温度特性做了深入研究。结果表明表面等离子体共振波长随待测样品折射率的增大向长波长方向漂移,平均折射率灵敏度为4.1×103 nm/RIU(RIU为单位折射率),高于已报道的结果;共振波长随待测样品温度的升高向短波长方向漂移,平均温度灵敏度为0.36nm/℃,故该光纤SPR传感器具有更强抗温度漂移能力和更高的高折射率灵敏度,其在生物化学传感领域有重要的应用。     

D型高双折射光子晶体光纤的折射率传感特性研究

基于表面等离子体共振(SPR)原理,分析了D型高双折射光子晶体光纤(HB-PCF)的折射率传感特性.模拟研究了抛磨角度对双折射、折射率传感灵敏度的影响.仿真结果表明:当抛磨面离纤芯的高度小于1.5倍占空比时,抛磨面离纤芯越近,双折射越小;随着抛磨角度的增加,双折射先增加后减小,折射率传感灵敏度随之减小;当抛磨角度为0°...     

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。     

侧边抛磨光纤的光谱调制型表面等离子体共振传感研究

表面等离子体共振传感是基于光学消逝波与金属表面等离子体波共振的一种高灵敏度、快速、无标记的测量方式。光纤的表面等离子体共振传感具有在线测量、体积小、抗电磁干扰等优点。为提高折射率传感灵敏度,采用轮式侧边抛磨法抛磨掉多模光纤的全部包层和部分纤芯,并采用溅射法在光纤抛磨区先镀高折射率的铬层然后镀金膜,制作了侧边抛磨光纤表面等离子体共振传感器。研究结果表明:该传感器可实现液体折射率在1.333~1.431RIU范围的测试,平均光谱灵敏度为4.11×103 nm·RIU-1,在1.417~1.431RIU折射率范围内光谱灵敏度达1.09×104 nm·RIU-1,折射率测量范围和光谱灵敏度均优于已报道的结果。此外,该传感器具有良好的稳定性与重复性实验测试,最小分辨率约为3.6×10-5 RIU。该传感器光谱灵敏度高、检测范围大、尺寸小及良好的稳定性与重复性等优点,可被用于食品检测、环境监测、生物医学检测等相关领域。     

光纤耦合三角形金柱阵列的等离子体共振

为了满足表面等离子体传感器高灵敏度、高线性以及较大测量范围的需求,提出侧边抛磨光纤耦合的三角形纳米金柱阵列等离子体共振传感模型.用有限元法仿真得出侧边抛磨光纤倏逝场激发出三角形纳米金柱的三种等离子体共振模式,分别为传输等离子体、三角形纳米金柱的本征等离子体和柱间等离子体,在传感器透射谱中呈现三个共振波谷.本征等离子体和柱间等离子体均属于局域等离子体,所对应的共振波谷对外界环境折射率的灵敏度较低但具有很高的线性度.传输等离子体对应的波谷随折射率变化灵敏度很高且呈非线性关系,优化后三角形金柱阵列设计中,当折射率为1.38~1.42RIU时,灵敏度高达12 882nm/RIU.该传感结构集成了侧边抛磨光纤的强倏逝场,具有传输等离子体的高灵敏度、局域等离子体的高线性度和大测量动态范围等优点,有重要的研究意义和实用价值.     

侧边抛磨的U型金溅射塑料光纤等离子体共振传感器

为了测量溶液折射率变化，对塑料光纤纤芯表面的纤芯-金层-液体的3层膜结构进行研究，制作了一种使用U型结构并结合侧边抛磨方法的表面等离子体共振传感器。将截取的一段塑料光纤弯曲成为U型，并在烘箱中通过较高温度使这段光纤的曲率固定，对弯曲部分的外表面进行抛光，暴露该位置塑料光纤芯层并在其上溅射金纳米薄膜层，将制备好的传感器浸入不同折射率的液体中，使用光谱分析仪观察光谱的移动。实验结果表明:当塑料光纤SPR传感器测量折射率变化范围在1.333~1.406的液体时，可以通过光谱观察到随着液体折射率的增大，等离子体共振吸收峰位置也不断地向波长增大的方向移动，并且二者之间存在线性关系，其灵敏度为7.5×10-4 RIU/nm。该传感器探头具有灵敏度高、小型化、易制备、低成本的特点。     

基于空气孔微结构光纤的表面等离子体共振折射率传感器北大核心CSCD

提出了一种基于表面等离子体共振(SPR)效应增强的光子晶体光纤折射率传感器。该传感器结构通过光纤熔接机拼接光子晶体光纤(PCF),在光子晶体光纤中间引入一个空气孔形成PCF-空气孔-PCF的光纤传感结构,随后使用磁控溅射镀膜工艺在其表面沉积一层薄金膜制备而成。实验探究了折射率及温度对传感器的响应。结果表明,在1.333~1.389的折射率范围内,所提出的传感器的平均折射率灵敏度为2 142.52 nm,且测量线性度为0.981,品质因子约13.10。实验结果表明该传感器对温度不敏感。相比于无空气孔的PCF传感结构,引入的空气孔增强了SPR效应,使得传感器拥有良好的共振峰深度。得益于上述优势,该类型传感器有望在生物医学、环境监测等领域得到应用。     

基于光子晶体光纤交叉敏感分离的磁场温度传感研究

提出了一种基于定向耦合效应和表面等离子共振效应的交叉敏感分离的磁场温度传感结构.在光子晶体光纤的一个特定空气孔中填充磁流体,利用磁流体的磁光效应和定向耦合效应形成磁场传感通道;在垂直方向的另一空气孔的内壁镀金纳米薄膜并填充甲苯液体,利用甲苯的温敏效应和表面等离子共振效应形成温度传感通道.对应输出谱出现两个损耗峰,测量损耗峰位置可以间接测出磁场强度和温度变化.通过理论计算()和结构优化,在90—270 Oe1 Oe=10~3/(4π) A/m范围内,磁场强度的灵敏度最高可达1.16 nm/Oe;在25—60?C范围内,温度的灵敏度可达-9.07 nm/?C.虽然填充的两种液体的折射率都受环境温度的影响,但通过建立灵敏度系数矩阵,可以消除磁场强度与温度的交叉敏感,实现磁场温度双参量的高灵敏度检测.     

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.     

Polarization detection analysis of dual-channel surface plasmon resonance sensing for silicone oils based on the D-shaped fiber with a central hole

We present and numerically characterize a dual channel surface plasmon resonance (SPR) sensor based on a D-shaped fiber with a central hole for silicone oil detections. The proposed design incorporates two metalized channels to facilitate the simultaneous detection of one group of silicone oils, which can consist of two different species. It has been demonstrated that the p-polarized input light can induce two peaks among surface plasmon resonance places, which come from the coupling between the core-guided mode and the fundamental surface plasmon polariton (SPP) modes at the D-shaped surface and around the central hole surface. However, the s-polarized input light can only induce one peak among surface plasmon resonance places, which comes from the coupling between the core-guided mode and the fundamental SPP mode around the central hole surface. The simulation results show that the characteristic responses of two channels independently correspond to the refractive index variations in the silicone oils with which they are in contact. A maximum sensitivity of 3500 nm/RIU (refractive index unit) and 4400 nm/RIU are achieved for channel A and B, respectively. This kind of sensor structure and polarization related demodulation method is promising in the simultaneous multi-analytes sensing applications in the future.     

Measurement of temperature and refractive index based on surface long-period gratings deposited onto a D-shaped photonic crystal fiber

We propose a surface long-period grating (LPG) based on a D-shaped photonic crystal fiber (PCF). The D-shaped PCF is fabricated by a side-polishing technique. The surface LPG based on periodic patterns of photoresist (PR) is formed by using the spin-coating and the standard contact lithography methods. Resonant coupling is created by the surface PR-LPG in the D-shaped PCF. The resonant peak shifts to longer wavelength as the ambient index is increased and shifts to shorter wavelength as the temperature is increased. The total wavelength shift is measured to be 122 nm in the refractive index range from 1 to 1.45 and the temperature sensitivity is measured to be −0.3 nm/°C in the temperature range from 30 to 100°C.     

基于游标效应的双芯光子晶体光纤温度传感器

设计了一种基于双芯光纤耦合效应和游标效应的高灵敏度温度传感器,传感器是由2个相差一定长度的双芯光子晶体光纤和单模光纤级联构成。双芯光子晶体光纤通过级联实现游标效应,同时对纤芯中间的气孔填充乙醇实现温度传感。仿真结果表明,该温度传感器在35 ℃～45 ℃范围内的平均温度灵敏度可达?20.37 nm/℃。与单纯依靠双芯光子晶体光纤能量耦合效应的传感器相比,该传感器的温度检测灵敏度提高了10倍。     

Optical refractometer based on large-core air-clad photonic crystal fibers

A large-core air-clad photonic crystal fiber-based sensing structure is described, which is sensitive to refractive index. The sensing head is based on multimodal interference, and relies on a single-mode/large-core air-clad photonic crystal fiber (PCF)/single-mode fiber configuration. Using two distinct large-core air-clad PCF geometries-one for refractive index measurement and the other for temperature compensation, it was possible to implement a sensing head sensitive to refractive index changes in water as induced by temperature variations. The results indicated the high sensitivity of this sensing head to refractive index variations of water, and a resolution of 3.4×10(-5) refractive index units could be achieved.     

Numerical analysis of a photonic crystal fiber based on two polarized modes for biosensing applications

This paper presents a theoretical study on a photonic crystal fiber plasmonic refractive index biosensor. The proposed photonic crystal fiber sensor introduces the concept of simultaneous detection with the linearly polarized and radially polarized modes because the sensing performance of the sensor based on both modes is relatively high, which will be useful for selecting the modes to make the detection accurately. The sharp single resonant peaks of the linearly polarized mode and radially polarized mode, are stronger and more sensitive to the variation of analyte refractive index than that of any other polarized mode in this kind of photonic crystal fiber. For linearly polarized mode and radially polarized mode, the maximum sensitivities of 10448.5nm per refractive index unit and 8230.7nm per refractive index unit can be obtained, as well as 949.8 and 791.4 for figure of merits in the sensing range of 1.33-1.45, respectively. Compared with the conventional Au-metalized surface plasmon resonance sensors, our device is better and can be applied as a biosensor.     

Polarization-dependent refractometer for discrimination of temperature and ambient refractive index

Transmission characteristics of polarization-dependent refractometer based on a surface long-period grating (SLPG) inscribed in a D-shaped photonic crystal fiber (PCF) are investigated. The birefringence of SLPG produces the separation of transmission spectra for TE and TM polarization modes. We also measure the sensitivities of PCF-based SLPG to temperature and external refractive index change depending on the input polarization states. The SLPG-based sensor exhibits different temperature and ambient index sensitivities corresponding to TE and TM polarization modes. Therefore, the SLPG inscribed in D-shaped PCFs can effectively discriminate temperature and ambient index sensitivities.     

激光泵浦碲化物产生中红外超连续谱数值模拟

对2 m波段脉冲激光泵浦碲化物光子晶体光纤产生中红外超连续谱进行了数值研究。通过材料的拉曼增益谱间接求得了对应的拉曼响应函数;由光子晶体光纤的材料折射率和波导结构,通过COMSOL软件获得了碲化物光子晶体光纤中基模等效折射率,计算了相应的色散曲线和限制损耗 ;利用自适应的分步傅里叶算法,模拟了中心波长为1.96m、峰值功率为20 kW的50 fs脉冲光泵浦碲化物光子晶体光纤时超连续谱的产生,当光纤长度为6 cm时,产生的中红外超连续谱波长范围为1.0~4.5 m。