Plasmon Resonance Refractive Index Sensor Research Articles

High sensitivity and wide detection range temperature and refractive index photonic crystal fiber sensor

A D-shaped surface plasmon resonance temperature and refractive index (RI) sensor based on photonic crystal fiber is proposed. The fiber core is composed of five air holes arranged in a pentagonal shape, which effectively improves the sensitivity. The gold film is used as a plasmonic material, and the mixture of ethanol and chloroform is used as a temperature sensitive liquid. A finite element method with higher accuracy and stronger applicability is used to study the performance of the sensor. The results indicate that when filling the mixture, the temperature sensor can detect the temperature in the range of 0 °C–60 °C. A maximum temperature sensitivity of 11.0 nm °C−1 is obtained by filling the mixture. The RI sensor can detect RI in the range of 1.13–1.40, with the wavelength range of 1.2–2.4 μm, and the maximum wavelength sensitivity reaches up to 21 000 nm RIU−1. The sensor can be used in biomedicine, environmental monitoring, food detection, temperature detection and other related fields, and has certain competitiveness and commercial value.

Hybrid magneto-plasmonic structure consisting of hexagonal periodic nanodisks array with giant transverse magneto-optical Kerr effect for sensing application

The present study proposes a theoretical design of the magneto-optical surface plasmon resonance (MOSPR) refractive index sensor that utilizes a magnetic field for modulating the dispersion of surface plasmon. This sensor based on the transverse magneto-optical Kerr effect (TMOKE) is constructed using a hybrid magneto-plasmonic film covered with an array of hexagonal periodic Au nanodisks. The structural parameters were optimized to obtain the Fano shape TMOKE response characterized by an extremely narrow bandwidth (0.00997°) and remarkably high amplitude (0.99). The excitation of the optimal surface plasmon resonance (SPR) and the resonance enhancement effect of multi-mode coupling enables us to achieve a surface sensitivity of 207.5 deg RIU−1 and a high figure of merit of the order of 104 RIU−1, surpassing conventional SPR and MOSPR sensors by at least one order of magnitude. The present study offers a comprehensive guideline for the design of high-performance magneto-plasmonic sensors, facilitating instrument miniaturization and manufacturing cost reduction.

A high sensitivity refractive index sensor based on microstructure fiber with simple structure and SPR effect

A novel dual-side polished photonic crystal fiber (PCF) based surface plasmon resonance (SPR) polarization filtering and refractive index (RI) sensor is presented in this paper. The cladding of PCF was composed of eight air holes and the outer surface was dual-sided polished and coated with gold film. Finite element method (FEM) was used for the simulation and design of the proposed sensor. Simulation results showed that sensor performance was better in analytes ranging from 1.33 to 1.42 RI. The wavelength and amplitude sensitivities at resonance wavelengths of 1269 and 995 nm were 27400 nm/RIU and −100.43 RIU−1 for an analyte of 1.42 and 1.41 RI, respectively, along with a spectral resolution of 3.64×10−6 RIU. Maximum loss of 52806 dB/m was obtained for an analyte of 1.41 RI towards Y-Polarization (Y-P). An extinction ratio of −105.374 dB was obtained using a fiber transferring length of 2 mm to achieve better polarization filtering effects. The proposed sensor is made of same size air holes which is easy to fabricate, cost effective, and shows better sensitivity and polarization filtering effects than several other sensors. It is expected that the sensor is suitable for wide RI detection range and capable of providing excellent polarization effect. The proposed sensor can be used for various applications including environmental detection, chemical sensing, biosensors, and pharmaceutical inspection.

Surface plasmon resonance refractive index sensor with progressive fiber expander

Surface plasmon resonance refractive index sensor with progressive fiber expander

A Tantalum Disulfide (TaS2) Mediated Long-Range Surface Plasmon Resonance Refractive Index Sensor with Improved Performance

A Tantalum Disulfide (TaS2) Mediated Long-Range Surface Plasmon Resonance Refractive Index Sensor with Improved Performance

Highly Sensitive Surface Plasmon Resonance Refractive Index Sensor Based on D-Shaped Dual‑Core Photonic Crystal Fiber with ITO Film

Highly Sensitive Surface Plasmon Resonance Refractive Index Sensor Based on D-Shaped Dual‑Core Photonic Crystal Fiber with ITO Film

Surface Plasmon Resonance Sensor Based on Waveguides Inscribed in No-Core Fiber

We present a surface plasmon resonance (SPR) refractive index sensor based on femtosecond laser inscribed waveguides in a no-core fiber sandwiched between two sections of single mode fibers. The waveguides inscribed have a trapezoidal structure which consists of three sections: two slant waveguides to direct light out and back into the core of single mode fiber and a straight waveguide close to and in parallel with the surface of no-core fiber. A thin layer of Cr+Ag is coated on the surface of NCF to cover the straight waveguide region. The device is compact and has good mechanical robustness. The experimental results obtained show that the device has a refractive index sensitivity of ~3234 nm/RIU in the refractive index range of 1.34-1.37, and is expected to have practical applications in the fields of bio-medicine and environmental monitoring.

High-sensitivity surface plasmon resonance refractive index sensor with high resolution based on D-shaped photonic crystal fiber

High-sensitivity surface plasmon resonance refractive index sensor with high resolution based on D-shaped photonic crystal fiber

Artificial neural network based optimization for Ag grated D-shaped optical fiber surface plasmon resonance refractive index sensor

This study reports the optimization of fiber optic SPR refractive index sensor parameters with the simulation of finite element method (FEM) and artificial neural network (ANN) model. To demonstrate the applicability of the algorithm, we examined an Ag-grated D-shaped fiber optic sensor configuration with 4 basic input parameters with the aim of reaching the highest sensitivity. Through the conventional optimization, the best parameter set appeared to be a 10 nm air gap distance between the gratings (a), 20 gratings (N), 50 nm residual cladding thickness (d), and 70 nm silver layer thickness (Ag_th) at the indices of 1.35 and 1.39 yielding a sensitivity of 3775 nm/RIU. A close match is found between the actual and predicted sensitivity. 199 input data obtained from FEM are used for training by Leave One Out Cross-Validation (LOOCV) approach with R-squared value of 0.98, and the trained model with R-squared value of 0.97 is implemented in the Genetic Algorithm. We achieved the sensitivity of 3890 nm/RIU at the predicted a, N, d, and Ag_th of 10 nm, 20, 50 nm, and 75 nm, respectively. Future studies may further improve these results by integrating other algorithms. This method may apply to different and more complex structures to observe the correlation between the parameters, cover an entire range of parameters, and get more accurate results, especially with a high number of inputs requiring less time and computing effort. The proposed method carries great potential to improve the sensing ability and bring a new perspective to the literature.

Cascaded Fiber-Optic Surface Plasmon Resonance Refractive Index Sensor with Temperature Self-Compensation

Cascaded Fiber-Optic Surface Plasmon Resonance Refractive Index Sensor with Temperature Self-Compensation

Experimental Study of Surface Plasmon Resonance Refractive Index Sensor Based on Side-Polished Few-Mode Fiber

Experimental Study of Surface Plasmon Resonance Refractive Index Sensor Based on Side-Polished Few-Mode Fiber

Plasmon resonance refractive index sensor of spiral-shaped plastic optical fiber surface

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500 μm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。

High Resolution and Stability Self-Reference Plasmonic Sensor With Metallic Grating on Multilayered Dielectric Cavity Substrate

In order to improve the sensing performance of surface plasmon resonance (SPR) refractive index (RI) sensor and avoid the negative effect of various environmental factors, a self-reference plasmonic sensor with high resolution and stability based on the combination of metallic grating and multilayered dielectric cavity is proposed in this article. The sensing mode, based on SPR in the metallic grating, is sensitive to the RI variations of the analyte. The guided mode resonances (GMRs), excited by the multilayered dielectric cavity, can be served as self-references due to the insensitivity to the analyte’s RI variations. It is verified that the sensitivity of 500 nm/RIU is achieved, and the smallest sensitivity of self-reference resonance is 0.83 nm/RIU; thus, the sensitivity ratio (stability) is up to 602. Also, a large figure of merit (FOM) of 238 RIU−1 in the sensor is realized and a high-quality factor of 4668 of self-reference mode with high resolution is achieved, which is much better than that of the previous works. The results provide a theoretical basis to design a highly sensitive self-reference plasmonic sensor and have a potential application in the industrial measuring instruments such as the sensor to measure water content in heavy oil.

Integration Aspects of Plasmonic TiN-based Nano-Hole-Arrays on Ge Photodetectorsin a 200mm Wafer CMOS Compatible Silicon Technology

During the last decade optical sensor technologies have attracted increased attention for various applications. Plasmon-based optical sensor concepts for the detection of refractive index changes that rely on propagating surface-plasmon polaritons at metal-dielectric interfaces or on localized plasmons in metallic nanostructures prove their potential for these application due to their fast detection speed, high specificity and sensitivities [1, 2]. Combining plasmonic structures directly with optoelectronic devices could enable a high level of integration, however, it represents a significant technological challenge to develop an on-chip solution for these concepts including the integration of sensor and detector components. Previous works demonstrated first approaches mainly for the integration of refractive index sensor components on wafer level [3, 4]. In [5] and [6] a proof-of-concept of a fully integrated on-chip solution with high sensitivities was presented, which can be easily combined with microfluidics [7] for potential applications in biosensing. In this concept, a nanohole array (NHA) was structured in a 100 nm thick aluminum layer on top of a vertical PIN germanium photodetector (GePD) with an intrinsic germanium sheet of 480 nm. This sensor concept relies on extraordinary optical transmission through the NHA [8]: Light transmission is only possible for narrow wavelength ranges determined by the NHA geometry which determine the transmission peaks at the resonance wavelength of the NHA. Thus, the NHA acts as a high quality wavelength filter. Due to the change in the refractive index, a material under test (MUT) contacting directly the surface of the NHA, provokes a shift of the wavelength maximum, which can be detected by measuring the photocurrent spectra of the GePD. While responsivities and sensitivities of (0 V) = 0.075 A/W and = 1200 nm/RIU could be attained in this proof-of-concept device [6, 7], the semiconductor device layers were deposited using molecular beam epitaxy (MBE). Furthermore the vertical PIN GePD was realized by a mesa procedure to enable large areas for top illuminated operations. These techniques are unsuitable for an industrial CMOS fabrication process with high throughput. Therefore, the development of a CMOS compatible technology process with low costs and high yields is an important step towards large-scale fabrication of this sensor concept.In this work we present the progress for the realization of a surface plasmon resonance (SPR) refractive index sensor in a 200 mm wafer Silicon based technology. One main challenge is the fabrication of a large area photodetector for top illuminated sensor devices. We developed a process, which is mainly based on the IHP electronic photonic integrated circuits (ePIC) technology [9]. This ePIC technology enables the production of waveguide coupled lateral PIN GePDs with high bandwidth and high responsivities [10]. However, these PDs are unsuitable for top illuminated applications because of their small germanium areas. Due to certain process conditions with respect to chemical mechanical polishing procedures there are limits for feasible large detector areas. Furthermore, large detector areas for lateral PIN GePDs would result in very low electric fields in the intrinsic zone where carriers are generated by photon absorption. Thus, very high voltages for reversed bias are necessary for sufficient carrier drifts.For the first time we have developed a modern detector design concept which is compatible to the IHP ePIC technology. This concept allows the realization of large area detectors of 1600µm² (40µm x 40µm) with optimized optical responsivities for top illuminated applications. The detector consists of several parallel connected lateral PIN GePDs. We designed different variations and varied Ge width and distance between neighboring GePDs in order to investigate process limits. The p- and n-doped regions were defined by dopant implantation using a photo resist mask. We used a finger-like design as implantation masks to enable one contact area for each p-doped and each n-doped region (Fig. 1). This contacting approach differs from the standard GePD offered in the IHP ePIC technology. We analyzed I-V characteristics in dependence of detector design and contacting scheme (Fig. 2). In addition, process adjustments for the optimization of the germanium quality were investigated to reduce dark currents and to improve optical responsivities (Fig.3).Titanium nitride (TiN) is very promising metallic alloy with respect to thickness homogeneity and low surface roughness. Therefore we used titanium nitride which was deposited by a sputtering process to develop plasmonic active NHA layers. Various process development runs were done to evaluate the NHA performance. Ellipsometry and atomic force microscope measurements were performed to characterize the quality of the TiN layer (Fig.4). Figure 1

Integration Aspects of Plasmonic TiN-based Nano-Hole-Arrays on Ge Photodetectorsin a 200mm Wafer CMOS Compatible Silicon Technology

In this work we present the progress in regard to the integration of a surface plasmon resonance refractive index sensor into a CMOS compatible 200 mm wafer silicon-based technology. Our approach pursues the combination of germanium photodetectors with metallic nanohole arrays. The paper is focused on the technology development to fabricate large area photodetectors based on a modern design concept. In a first iteration we achieved a leakage current density of 82 mA/cm2 at reverse bias of 0.5 V and a maximum optical responsivity of 0.103 A/W measured with TE polarized light at λ = 1310 nm and a reversed bias of 1 V. For the realization of nanohole arrays we used thin Titanium nitride (TiN) layers deposited by a sputtering process. We were able to produce very homogenous TiN layers with a thickness deviation of around 10 % and RMS of 1.413 nm for 150 nm thick TiN layers.

Refractive index and temperature sensors of V-cut photonic crystal fibers based on surface plasmon resonance

In this paper, a surface plasmon resonance refractive index and temperature sensor based on V-cut photonic crystal fiber (PCF) is proposed. The proposed structure is studied and analyzed using the finite element method (FEM). The sensing area is a V-shaped cut groove, and the cases when the cut angle is positive, 0° and negative are discussed and compared. The results show that when the cutting angle is 15°, the optimal sensing performance can be obtained compared with other cutting angle. By optimizing other structural parameters when the cutting angle is 15°, in the refractive index range of 1.34–1.38, the average sensitivity of the refractive index sensor is 10,500 nm/RIU, and the maximum sensitivity is 52,500 nm/RIU. The average sensitivity is 5.57 nm/°C in the range of 85 ℃–145 ℃ as a temperature sensor. Due to the simple structure and high sensitivity of the design, it can be used for real-time monitoring of analytes in medical, biochemical and environmental monitoring.

Wide refractive index detection range surface plasmon resonance sensor based on D-shaped photonic crystal fiber

We propose and simulate a surface plasmon resonance (SPR) refractive index (RI) sensor based on a novel D-shaped photonic crystal fiber. We used an open air hole coated with gold film to improve SPR effect. The sensor uses photonic crystal fiber with the same air holes diameter. The effects of structural parameters on resonance spectrum were analyzed by finite element method (FEM). Three SPR peaks were obtained in the wavelength range of 800–1300 nm. The maximum sensitivity is 5626.86 nm/RIU and the maximum resolution is 1.78 × 10−5 RIU at the refractive index of 1.38. The simulation results show that the refractive index detection range of the sensor is 1.26–1.38. Compared with other D-shaped structures, our sensor can measure larger RI ranges of the analyte.

Design and modelling of reconfigurable surface plasmon resonance refractive index sensor employing graphene and Sb2S3 for detection of dengue virus

This research addresses the design and analysis of a highly sensitive reconfigurable surface plasmon resonance (SPR) sensor for the detection of dengue virus. The SPR sensor is designed with successive layers of SF11 prism, Ag, graphene, antimony trisulphide (Sb2S3), and sensing medium. The sensing medium is infiltrated with various normal and dengue infected blood components like plasma, platelets, and hemoglobin. The angular reflectivity is investigated by employing the well-established transfer matrix method. Geometrical parameters like thickness of the Ag layer and number of graphene layer are sensibly optimized to attain high performance. The proposed structure is modelled in COMSOL Multiphysics environment to investigate the electric field intensity near the Sb2S3 and sensing medium interface. It is perceived that by switching the phase of Sb2S3 from amorphous to crystalline, the sensitivity is increased from 124.61°/RIU to 180.76°/RIU, 96.66°/RIU to 225.75°/RIU, and 127.42°/RIU to 216.57°/RIU for plasma, platelet and hemoglobin cell respectively.

Highly sensitive gold-coated surface plasmon resonance photonic crystal fiber sensor in near-infrared region

In this research paper, we propose a highly sensitive yet simple design hexagonal photonic crystal fiber (PCF) core-based surface plasmon resonance (SPR) refractive index (RI) sensor. The unknown target analyte and the plasmonic material, gold (Au) are placed at the exterior of the sensor surface for the feasibility of the operation. Twelve purely circular air-holes in two rings constitute PCF structure which makes the fabrication process realizable and practical. Numerical investigations are carried out utilizing the full-vector finite element method (FEM) to obtain the sensing performance of the PCF-SPR structure. After optimizing the structural parameters, the proposed PCF-SPR sensor obtains the highest wavelength sensitivity of 36000 nm/RIU and the highest amplitude sensitivity of 642.53 RIU-1, for an analyte RI range of 1.395 to 1.420 in the near-infrared wavelength regime (800 nm − 1200 nm). Aside from that, the sensor attained the maximum wavelength resolution and amplitude resolution of 2.77×10-6 RIU and 1.55×10-5RIU-1 respectively to assure excellent detection accuracy of smallest RI changes. Furthermore, the sensor achieved the highest Figure of Merit of 257.14 RIU-1. Thus, the proposed PCF-SPR sensor has the potential to detect unknown RI in a variety of applications including biosensing.

Highly Sensitive Surface Plasmon Resonance Refractive Index Multi-Channel Sensor for Multi-Analyte Sensing

In this work, we propose a simple yet highly sensitive multi-channel hexagonal photonic crystal fiber (PCF) based surface plasmon resonance (SPR) refractive index (RI) sensor for detecting multiple analytes. The target analytes and the plasmonic materials, such as, gold (Au), Au with Tantalum Pentoxide (Ta <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> ) and Au with Titanium Dioxide (TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) are employed around the exterior of the sensor for the feasibility of the operation. Twelve circular air-holes in two layers constitute the fiber structure which makes the fabrication process easy and realizable. Numerical investigations are carried out employing a full-vector finite element method (FEM) to obtain the sensing performance of the PCF-SPR structure. After optimizing the structural parameters, the sensor achieves maximum wavelength sensitivity (WS) of 38100 and 21600 nm/RIU, for channels-1 and -2, respectively. For channel-3, the sensor achieves a maximum WS of 45800 nm/RIU. To the best of our knowledge, the proposed sensor achieves better performance in terms of wavelength sensitivity, wavelength resolution, amplitude sensitivity, amplitude resolution, figure of merit, etc., compared to the existing literature. In the case of cancerous cell detection, the proposed sensor achieves maximum WS and amplitude sensitivity of 12000 nm/RIU and −2440.30 RIU <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> , respectively, for HeLa cells. We envisage that the proposed sensor has a high potential to detect unknown RI for different chemical and biomedical applications due to its superior performance, simple design, and multi-analyte detection ability.