Extra-broad Photonic Crystal Fiber Refractive Index Sensor Based on Surface Plasmon Resonance

Plasmonics - We propose and investigate a photonic crystal fiber (PCF) refractive index sensor with triangular lattice and four large-size channels based on surface plasmon resonance. In such...     

Analysis of Graphene-Based Photonic Crystal Fiber Sensor Using Birefringence and Surface Plasmon Resonance

Plasmonics - We present and numerically characterize a photonic crystal fiber (PCF)-based surface plasmon resonance (SPR) sensor. By adjusting the air hole sizes of the PCF, the effective...     

Highly Sensitive Surface Plasmon Resonance Based D-Shaped Photonic Crystal Fiber Refractive Index Sensor

In this article, a D-shaped photonic crystal fiber based surface plasmon resonance sensor is proposed for refractive index sensing. Surface plasmon resonance effect between surface plasmon polariton modes and fiber core modes of the designed D-shaped photonic crystal fiber is used to measure the refractive index of the analyte. By using finite element method, the sensing properties of the proposed sensor are investigated, and a very high average sensitivity of 7700 nm/RIU with the resolution of 1.30 × 10^?5 RIU is obtained for the analyte of different refractive indices varies from 1.43 to 1.46. In the proposed sensor, the analyte and coating of gold are placed on the plane surface of the photonic crystal fiber, hence there is no necessity of the filling of voids, thus it is gentle to apply and easy to use.     

U-Shaped Photonic Crystal Fiber Based Surface Plasmon Resonance Sensors

A surface plasmon resonance sensor based on a U-shaped photonic crystal fiber with a rectangular lattice has been designed through finite element method. The U-shaped fiber exhibits not only stronger mechanical strength but also better sensor performance than our previous scheme. The upper detection limit extends to higher analyze refractive index, 1.384, for phase interrogation. We introduce a ratio to evaluate the impact of higher order plasmonic mode. For wavelength modulation scheme, the parameter to describe the performance of a sensor is chosen to be the figure of merit, which can be up to 533.8[RIU^?1] around complete coupling condition.     

Tunable Surface Plasmon Resonance Sensor Based on Photonic Crystal Fiber Filled with Gold Nanoshells

We present a photonic crystal fiber (PCF)-based surface plasmon resonance (SPR) sensor, whose operating wavelength range is tunable. Gold nanoshells, consisting of silica cores coated with thin gold shells, are designed to be the functional material of the sensor because of their attractive optical properties. It is demonstrated that the resonant wavelength of the sensor can be precisely tuned in a broad range, 660 nm to 3.1 μm, across the visible and near-infrared regions of the spectrum by varying the diameter of the core and the thickness of the shell. Furthermore, the effects of structural parameters of the sensor on the sensing properties are systematically analyzed and discussed based on the numerical simulations. It is observed that a high spectral sensitivity of 4111.4 nm/RIU with the resolution of 2.45 × 10^?5 RIU can be achieved in the sensing range of 1.33–1.38. These features make the sensor of great importance for a wide range of applications, especially in biosensing.     

Highly Sensitive Dual-core Photonic Crystal Fiber Based on a Surface Plasmon Resonance Sensor with Gold Film

Plasmonics - A highly sensitive surface plasmon resonance (SPR) sensor comprising a dual-core photonic crystal fiber (PCF) is designed to detect minute changes in analyte refractive indices (RIs)...     

Refractive Index Sensor Based on Surface Plasmon Resonance Excitation in a D-Shaped Photonic Crystal Fiber Coated by Titanium Nitride

Plasmonics - In this paper, a plasmonic refractive index sensor using a D-shaped photonic crystal fiber coated by titanium nitride has been proposed. The interaction and interplay between fiber...     

Analysis of Dual-Core Photonic Crystal Fiber Based on Surface Plasmon Resonance Sensor with Segmented Silver Film

Plasmonics - A dual-core photonic crystal fiber (PCF) based on surface plasmon resonance (SPR) sensor with segmented silver film (silver nanoslit) deposited in microfluidic channel is designed. The...     

High-performance Opening-up Dual-core Photonic Crystal Fiber Sensors Based on Surface Plasmon Resonance

Plasmonics - Nowadays, plasmonic sensors based on photonic crystal fiber (PCF) attracted a great deal of attention in the field of optical sensing. Opening-up dual-core photonic crystal fibers...     

Design of a Single-Polarization Single-Mode Photonic Crystal Fiber Filter Based on Surface Plasmon Resonance

We design a single-polarization single-mode photonic crystal fiber filter based on surface plasmon resonance. The finite element method is employed to evaluate the characteristics of the filter. The proposed fiber is devised such that there is a great discrepant confinement loss between two polarizations of x and y by varying two air holes in the cladding region, which is composed of hexagonal structural air holes in pure silica selectively filling with gold wires. Numerical simulations show that single-polarization single-mode operation waveband can be tuned by adjusting the parameters of the photonic crystal fiber. The confinement losses of the unwanted polarization can reach to 126.10 and 326.30 dB/cm in the wavelengths of 1.31 and 1.55 μm, while the corresponding confinement losses of the wanted polarized mode are only 0.08 and 1.20 dB/cm, respectively. Furthermore, the crosstalk can come to a maximum of 120.34 and 310.41 dB in the two communication bands. The bandwidths of the fiber designed for 1.31 and 1.55 μm are, respectively, 20 and 60 nm, which may be found useful applications for fiber polarizer.     

Materials Effect in Sensing Performance Based on Surface Plasmon Resonance Using Photonic Crystal Fiber

Plasmonics - This article explores the effect of sensing performances with subject to change in different types of material and this study is carried out by the support of plasmon-coated photonic...     

Dual-Channel Surface Plasmon Resonance–Based Photonic Crystal Fiber Sensor with Metal-Ta2O5 Coating at Near-infrared Wavelength

Plasmonics - This work proposes a novel multi-channel photonic crystal fiber (PCF) based on surface plasmon resonance (SPR) technique where Au-Ta2O5 layer and Ag-Ta2O5 layer are selected as...     

Sensitivity of Optical Fiber Sensor Based on Surface Plasmon Resonance: Modeling and Experiments

In this paper, surface plasmon resonance curves of an optical fiber-based sensor were investigated. From an experimental and theoretical perspective, the response curves were analyzed and discussed. Precisely, such curves were calculated by modeling the analyte/metallic layer interface using a multilayer system, including the effects of roughness. Then, the experimental response curves observed in solutions with different refractive indices were compared to the simulated curves. Good agreement was obtained with respect to the resonance peak location and the shape of the curves. Consequently, these results enabled us to predict the ideal functioning conditions of the sensor, i.e., the working parameters corresponding to the best sensitivities of detection.     

D-Shaped Photonic Crystal Fiber–Based Surface Plasmon Resonance Biosensors with Spatially Distributed Bimetallic Layers

This paper deals with the development and analysis of D-Shaped photonic crystal fiber (PCF) biosensors using surface plasmon resonance (SPR). A thin metal layer is deposited on the outer flat surface of the PCF that behaves as the plasmonic material. Analyte is filled in the outermost peripheral region of metal layer. Finite element method (FEM) with perfectly matched layer (PML) is applied to analyze the proposed sensors. Mode analysis is performed on the proposed structures to evaluate various parameters of SPR-based PCF sensors. Three D-shaped PCF structures have been proposed with silver (Ag), gold (Au) and two-half layers of both (Ag-Au) on its flat surface. The first two structures are analyzed to the range of wavelength where the SPR will occur to facilitate understanding of the third structure. It is observed that the structures with one metal have only one sensitive plasmonic peak whereas the structure with two metal layers has two sensitive plasmonic peaks, making it suitable candidate for two-molecule sensing present in a sample analyte. Good sensitivities and resolutions are achieved for both plasmonic peaks.

     

A Highly Sensitive Dual-Core Photonic Crystal Fiber Based on a Surface Plasmon Resonance Biosensor with Silver-Graphene Layer

A highly sensitive dual-core photonic crystal fiber based on a surface plasmon resonance (PCF-SPR) biosensor with a silver-graphene layer is described. The silver layer with a graphene coating not only prevents oxidation of the silver layer but also can improve the silver sensing performance due to the large surface-to-volume ratio of graphene. The dual-core PCF-SPR biosensor is numerically analyzed by the finite-element method (FEM). An average spectral sensitivity of 4350 nm/refractive index unit (RIU) in the sensing range between 1.39 and 1.42 and maximum spectral sensitivity of 10,000 nm/RIU in the sensing range between 1.43 and 1.46 are obtained, corresponding to a high resolution of 1 × 10⁻⁶ RIU as a biosensor. Our analysis shows that the optical spectra of the PCF-SPR biosensor can be optimized by varying the structural parameters of the structure, suggesting promising applications in biological and biochemical detection.

     

A Polarization Filter Based on a Novel Photonic Crystal Fiber with a Gold-Coated Air Hole by Using Surface Plasmon Resonance

A novel design of a polarization filter based on photonic crystal fiber (PCF) is proposed in this paper. With the introduction of a gold-coated air hole, the resonance strength is much stronger in y-polarized direction than in x-polarized direction at some particular wavelengths, which is due to the metal surface plasmon effects. At the wavelength of 1.31 μm, the loss of y-polarized mode is 2138.34 dB/cm while the loss is very low in x polarization. Furthermore, the loss peak can be flexibly adjusted from the wavelength of 1.26 to 1.56 μm by changing the thickness of a gold layer, and the loss in y polarization can be kept above 1200 dB/cm. The significant loss in y polarization makes this PCF a good candidate for developing a polarization filter with high performance.     

Cancer Detection with Surface Plasmon Resonance-Based Photonic Crystal Fiber Biosensor

Plasmonics - In this study, early cancer detection of a single living cell is investigated by employing a surface plasmon resonance (SPR)-based photonic crystal fiber (PCF) biosensor structure. The...     

Electrically Tunable Fiber Optic Sensor Based on Surface Plasmon Resonance

The response of optical fiber surface plasmon resonance (SPR) sensor to potential is monitored in real time. The potential-induced reflectance of a gold-coated optical fiber SPR probe is dependent on potential step width and ionic strength. Wider potential step and stronger ionic strength are generally able to enhance the reflectance and accelerate the response time. The specifically adsorptive anion Cl^? provides a pronounced effect on a potential-dependent SPR probe. The exclusive contact of the SPR probe with anion Cl^? could significantly slow down the optical response. The work offers opportunities for optical fiber SPR probes to characterize the electrochemical application.     

Surface Plasmon Resonance-Based Tapered Fiber Optic Sensor: Sensitivity Enhancement by Introducing a Teflon Layer Between Core and Metal Layer

Surface plasmon resonance (SPR)-based tapered fiber optic sensor with Teflon as a dielectric sandwiched between metal and tapered fiber core is proposed. The sensitivity of the sensor has been maximized using different combinations of metal and Teflon layer thicknesses for a given taper ratio. The study shows that the sensitivity of the sensor with the introduction of dielectric (Teflon) increases with the increase in the taper ratio. The maximum sensitivity achieved for a given taper ratio is around 15 times higher than the general SPR-based fiber optic sensor.