Fiber Based Surface Plasmon Resonance Research Articles

A Review of Apta-POF-Sensors: The Successful Coupling between Aptamers and Plastic Optical Fibers for Biosensing Applications

Aptamers represent the next frontier as biorecognition elements in biosensors thanks to a smaller size and lower molecular weight with respect to antibodies, more structural flexibility with the possibility to be regenerated, reduced batch-to-batch variation, and a potentially lower cost. Their high specificity and small size are particularly interesting for their application in optical biosensors since the perturbation of the evanescent field are low. Apart from the conventional plasmonic optical sensors, platforms based on silica and plastic optical fibers represent an interesting class of devices for point-of-care testing (POCT) in different applications. The first example of the coupling between aptamers and silica optical fibers was reported by Pollet in 2009 for the detection of IgE molecules. Six years later, the first example was published using a plastic optical fiber (POF) for the detection of Vascular Endothelial Growth Factor (VEGF). The excellent flexibility, great numerical aperture, and the large diameter make POFs extremely promising to be coupled to aptamers for the development of a sensitive platform easily integrable in portable, small-size, and simple devices. Starting from silica fiber-based surface plasmon resonance devices, here, a focus on significant biological applications based on aptamers, combined with plasmonic-POF probes, is reported.

Bending analysis of multi-analyte photonic crystal fiber based surface plasmon resonance sensor

Bending analysis of multi-analyte photonic crystal fiber based surface plasmon resonance sensor

Pie-shaped photonic crystal fiber based surface plasmon resonance sensor for multi-analyte sensing purposes

Pie-shaped photonic crystal fiber based surface plasmon resonance sensor for multi-analyte sensing purposes

Review of Fiber Optic Displacement Sensors

Displacement measurements are of significant importance in a variety of critical scientific and engineering fields such as gravitational wave detection, geophysical research, and manufacturing industries. Due to the inherent advantages such as compactness, high sensitivity, and immunity to electromagnetic interference, in recent years, fiber optic sensors have been widely used in an expansive range of sensing applications, ranging from infra-structural health monitoring to chemical and biological sensing. Of particular interest here, fiber optic displacement sensors have gained wide interest and have evolved from basic intensity modulation-based configurations to more advanced structures, such as fiber Bragg grating-based, interferometric configurations, etc. This paper reviews specifically the advanced fiber optic displacement sensing techniques that have been developed in the past two decades. Details regarding the working principle, sensor design, and performance measures of fiber Bragg gratings-based, interferometers-based (including the Fabry-Perot interferometer, the Michelson interferometer, and the multimode interferometer), microwave photonics-based, and surface plasmon resonance-based fiber optic displacement sensors are given. Challenges and perspectives on future research in the development of practical and high-temperature tolerant displacement sensors are also discussed.

An Optical Fiber-Based Surface Plasmon Resonance Sensor for Simultaneous Measurement of Temperature and Magnetic Field Intensity

In this article, a surface plasmon resonance (SPR) sensor was designed based on the no-core optical fiber (NCF) for the simultaneous measurement of magnetic field intensity and ambient temperature. The sensor structure was mainly comprised of two NCF segments spliced between two multimode optical fibers, and different metal films were deposited on the NCF surface to generate the SPR effect: the NCF coated by silver and wrapped by MF was used for magnetic field sensing and the NCF coated by gold and wrapped by PDMS was used for temperature sensing. The proposed sensor successfully avoided the influence of temperature on magnetic field sensing, and vice verse. Detailed experimental investigation showed that in the magnetic field intensity range of 0–248 Gs, a maximum sensitivity of 132 pm/Gs was obtained with good linearity (coefficient of determination 0.991), and in the temperature range of 20 °C–60 °C, the corresponding sensitivity was −1.960 nm/°C with a linearity higher than 0.997. The proposed sensor can perform an accurate sensing even in weak magnetic field environment and simultaneously provide information about temperature variation. Being simple in structure, easy to manufacture and stable in performance, this sensor provides a feasible solution for the integration and miniaturization of multi-parameter measurement.

Ag-Ni bimetallic film on CaF2 prism for high sensitive surface plasmon resonance sensor

Ag-Ni bimetallic film on CaF2 prism for high sensitive surface plasmon resonance sensor

Design of surface plasmon resonance based both side polished photonic crystal fiber for highly efficient refractive index sensor

In this paper, both sides flat photonic crystal fiber-based surface plasmon resonance (PCF-SPR) sensor has been proposed. In this external sensing mechanism based sensor, we have used gold as plasmonic material with an adhesive TiO2 layer over it, enhancing the interaction between analyte channel and gold metal. Using the wavelength interrogation and amplitude interrogation method, the maximum wavelength and amplitude sensitivities are obtained 22,800 nm/RIU and 947 RIU−1, respectively, for analyte range 1.30–1.40 with a maximum wavelength resolution of 4.38 × 10−6. With Full-width half maxima (FWHM) around 45 nm, the sensor provides a high figure of merit (FOM) 507 RIU−1. The proposed sensor can be fabricated from newly available technologies such as the sol-gel method, stack and draw method for several practical applications in the bio-medical field, bio-chemical field to provide higher and accurate sensing results. The presented sensor has also played a vital role in cancer cell detection with higher sensing performance.

Surface Plasmon Plastic Optical Fiber Resonance with Multi-Layer as Chemical Sensor

A chemical optical fiber sensor based on surface plasmon resonance (SPR) was developed and implemented using multimode plastic optical fiber. The sensor is used to detect and measure the refractive index and concentration of various chemical materials (Urea, Ammonia, Formaldehyde and Sulfuric acid) as well as to evaluate the performance parameters such as sensitivity, signal to noise ratio, resolution and figure of merit. It was noticed that the value of the sensitivity of the optical fiber-based SPR sensor, with 60nm and 10 mm long, Aluminum(Al) and Gold (Au) metals film exposed sensing region, was 4.4 μm, while the SNR was 0.20, figure of merit was 20 and resolution 0.00045. In this work a multimode plastic optical fiber with a core diameter of 980 μm, fluorinated polymer cladding of 20 μm and a numerical aperture of 0.51 was used.

Gold-Immobilized Photonic Crystal Fiber-Based SPR Biosensor for Detection of Malaria Disease in Human Body

This article presents the photonic crystal fiber (PCF) based surface plasmon resonance (SPR) biosensor for early detection of malaria disease in humans by measurement of the variation of red blood cells (RBCs). In the proposed PCF, two layers of air holes are arranged in a hexagonal lattice structure and a thin film of gold-coating is used over PCF for the occurrence of SPR phenomena. It occurs when surface plasmon polariton (SPP)-mode coupled with the core-mode during phase-matching conditions. Malaria infected RBCs samples are filled into the PCF, which have own refractive index (RI) that shift the SPR resonance wavelength during confinement loss measurement. The resonance wavelength of malaria-infected RBCs samples is different from their normal RBCs samples due to the difference in RI of infected and normal RBCs samples. The proposed work is helpful in the detection of different stages of malaria-infected RBCs such as ring phase, trophozoite phase and Schizont phase by measuring the shift in resonance wavelength. The calculated wavelength sensitivities of the proposed sensor for the ring phase, trophozoite phase and Schizont phase RBCs are 13714.29 nm/RIU, 9789.47 nm/RIU, and 8068.97 nm/RIU, respectively in x-polarized direction and 14285.71 nm/RIU, 10000 nm/RIU, and 8206.9 nm/RIU, respectively in y-polarized direction with the maximum detection limit of 0.029. The proposed PCF-based SPR biosensor is suitable for the early diagnosis of malaria disease due to its enhanced sensing performance (low detection limit and high sensitivity).

High-performance surface plasmon resonance refractometer based on a no-core fiber coated with a silver film

Owing to their high sensitivity, surface plasmon resonance (SPR)-based sensors depict broad application prospects in biochemical detection, environmental monitoring, and food safety. In this paper, an optical fiber-based SPR sensor is proposed and demonstrated for the refractive index (RI) detection of liquid samples. This sensor is composed of a multimode fiber (MMF), a no-core fiber (NCF), and another MMF that is connected in sequence. The length of the NCF is 2 cm. A thin silver film is deposited on the NCF surface to stimulate the SPR effect. Experimental results indicated that the shift amount of resonance dip wavelength is as high as 303.6 nm as RI increases from 1.333 to 1.4107. A sensitivity of 2507.58 nm/RIU with a fitting linearity R 2 of 0.9931 is obtained in the lower RI region of 1.333–1.3723, while the sensitivity and R 2 reaches 5228.21 nm/RIU and 0.97395, respectively, in the higher RI region of 1.3723–1.4107. Compared with previously reported RI sensors, the proposed fiber optic SPR sensor exhibits the advantages of simple structure, small volume, low cost, high sensitivity, and wide detection range.

Graphene oxide biohybrid layer enhances sensitivity and anticorrosive properties in refractive index sensor

Graphene-based materials are capable of enhancing the refractometric response of prism- and optical fiber-based surface plasmon resonance (SPR) sensors; however, complicated multistep and time-consuming attaching processes could limit their practical applications. Herein, for the first time, we demonstrate the immobilization of graphene oxide (GO) submicrometric sheets onto the surface of a gold-coated single-mode fiber using a coating of fungal self-assembling proteins, the hydrophobins (HFBs), as an adhesive nanolayer. Hetero-core fiber tip SPR structures used in this study, consisting of a mirrored multimode–single-mode fiber structure coated with different thin layers (a chromium layer of 3 nm and a gold layer of 30 nm on top) exhibited a refractive index sensitivity (SRI) of 1842 nm RIU−1 (RIU: refractive index unit) at a refractive index (RI) of 1.36. Self-assembly of GO over the SPR fiber tip via HFB, offered an enhancement of up to 20% in the SRI. Moreover, this HFB-GO coating prevented degradation of the Al thin film mirror caused by corrosive salt-water solutions. The process is very simple, harmless, rapid (around 15 min) and scalable, as it is mostly based on one plasma treatment, which can be performed in large chambers and two dip coating steps, in liquid baths. All these features make the use of self-assembled bio/non-bio hybrid coating a green industrial method to improve the performance of SPR fiber biosensors, if compared with traditional chemical methods. Materials applied in this technology, fungal proteins and derivatives of graphite, are sustainable and largely available.

An Enhanced Plastic Optical Fiber-Based Surface Plasmon Resonance Sensor with a Double-Sided Polished Structure.

An enhanced plastic optical fiber (POF)-based surface plasmon resonance (SPR) sensor is proposed by employing a double-sided polished structure. The sensor is fabricated by polishing two sides of the POF symmetrically along with the fiber axis, and a layer of Au film is deposited on each side of the polished region. The SPR can be excited on both polished surfaces with Au film coating, and the number of light reflections will be increased by using this structure. The simulation and experimental results show that the proposed sensor has an enhanced SPR effect. The visibility and full width at half maximum (FWHM) of spectrum can be improved for the high measured refractive index (RI). A sensitivity of 4284.8 nm/RIU is obtained for the double-sided POF-based SPR sensor when the measured liquid RI is 1.42. The proposed SPR sensor is easy fabrication and low cost, which can provide a larger measurement range and action area to the measured samples, and it has potential application prospects in the oil industry and biochemical sensing fields.

The surface plasmon resonance-based fiber optic sensors: A theoretical comparative study with 2D TMDC materials

In this study, the surface plasmon resonance-based fiber optic sensor using two-dimensional (2D) TMDC materials covering the Au/Ag bimetallic layer has been reported. Since MoS2, MoSe2, WS2, and WSe2 are the most popular ones, they are constructed as the resonant layer of the sensor. The layer-dependencies and heterostructures of the TMDC materials are examined for the determination of their effect on the performance of the SPR sensor. The performance parameters of the SPR sensor, the sensitivity, accuracy, and figure of merit, are calculated with the help of the MATLAB simulations. It is found out that considering the very small change in the refractive index of the sensing medium (0.0025), the monolayer MoSe2 has the highest sensitivity value of 8096 nm/RIU. In contrast, the monolayer WS2 has the highest accuracy and figure of merit values of 0.34 and 136.89 RIU−1, respectively. This study will be benefited for a better understanding of the performance of the SPR based fiber optic sensor depending on the number of layers of TMDC materials and based on their heterostructures.

Numerical exploration of external sensing scheme based photonic crystal fiber surface plasmonic sensor with different noble plasmonic materials and their alloys

The selection of appropriate plasmonic material is extremely crucial for getting good sensing performance from photonic crystal fiber-based surface plasmon resonance (PCF-SPR) sensors. The numerical investigation of PCF-SPR sensors is still limited to conventional plasmonic materials in most existing studies. Recent researches show that some alloys can also be potential candidates as plasmonic materials for their remarkable plasmonic characteristics. This article presents a numerical analysis of a simple designed external sensing scheme based PCF-SPR sensor employing different noble plasmonic materials and their alloys. The sensor's design is kept very simple to ease the fabrication complexity, and the sensing ingredient is placed outside of the main structure. To investigate the sensing performance of the sensor, we have chosen gold, silver, and copper as noble plasmonic materials and gold-silver (30 %–70 %), gold-silver (70 %−30 %), and copper-zinc (90 %−10 %) as alloys. From the obtained results, it is observed that the reported sensor shows maximum amplitude sensitivity (AS) of 9759.00 RIU−1 and figure of merit (FOM) of 923.07 RIU−1 when the silver coating is used. Moreover, the reported sensor shows maximum spectral sensitivity (SS) of 26,000 nm/RIU and resolution of 3.84 × 10-6 with copper-zinc (90 %−10 %) alloy. Because of its highly sensitive performance, this sensor can be an impressive appliance for the identification of organic substances, biological fluids, and samples.

Plasmonic Biosensor for Low-Index Liquid Analyte Detection Using Graphene-Assisted Photonic Crystal Fiber

We report a sensitive D-shaped photonic crystal fiber-based surface plasmon resonance (PCF-SPR) sensor with linear sensing performance and a broad detection range for low refractive index (RI) liquid analytes ranging from 1.27 to 1.37 with possible extension beyond this range. We examine three combinations of materials (silver only, graphite on silver, and graphene on silver) as plasmonic nanofilm for the PCF-SPR and demonstrate that graphene-assisted PCF has the best overall performance. We show that graphene coating of silver nanofilm improves the sensitivity and the overall figure of merit of the sensor, besides the practical benefit of protecting the silver nanofilm from surface oxidation. Furthermore, we propose two distinct ways of analyte sensing based on filling patterns where the liquid analyte can be filled internally into the top two air holes of the PCF, or externally into a rectangle channel at the top of the fiber. In the internal filling detection scheme, the graphene-assisted PCF-SPR sensor demonstrates ultra-linearity, a detection range of 0.1 refractive index unit (RIU) between 1.27 and 1.37, an average linear spectral sensitivity of 2320 nm/RIU, and a maximum amplitude sensitivity of 192 RIU−1 for 1150 nm excitation. In the external filling detection scheme, the PCF-SPR exhibits extremely large sensitivities with a maximum spectral sensitivity of 22,400 nm/RIU close to analyte RI of 1.33, and a maximum figure of merit (FOM) of 127 which is approximately five times larger than that of the similar reported PCF-SPR sensors in the literature. The combination of a broad detection range for low-index analytes, large sensitivities, design flexibility, and stability against surface oxidation renders our proposed sensor as an interesting candidate for biosensing applications in chemistry, biology, and medicine.

Plasmonics: A Necessity in the Field of Sensing-A Review (Invited)

ABSTRACT Surface plasmon resonance (SPR) and surface plasmon polariton (SPP) is substantially developing optical sensing approaches that have been working in a wide range of applications, such as biological and chemical analyte detection, bioimaging, food safety, and environmental monitoring to security. Recently, optical fiber-based Surface plasmon resonance (SPR) sensors has gained much attention due to the invention of Photonic crystal fiber (PCF) and microstructured optical fiber (MOF) which offer compact size and light regulatory competencies in unmatched ways. Moreover, the field of sensing has witnessed another type of plasmonic sensors which are based on metal-insulator-metal (MIM) waveguide structure utilizing surface plasmon polariton (SPP) phenomena. This review paper provides an insight into the technological growths in plasmonic sensors based on optical fibers and the MIM platform. We believe that this paper is one of its kind which provides a diverse range of novel plasmonic sensor structures to its readers.

Parallel Polished Plastic Optical Fiber-Based SPR Sensor for Simultaneous Measurement of RI and Temperature

In this work, a parallel polished plastic optical fiber (POF)-based surface plasmon resonance (SPR) sensor is proposed and demonstrated for simultaneous measurement of refractive index (RI) and temperature. The sensor is fabricated by double polishing the POF symmetrically and depositing a layer of gold film on both sides of the polished regions. By coating the polydimethylsiloxane (PDMS) layer on one of the polished sides, another resonance peak for the temperature sensing can be observed in the transmission spectrum. When the RI and temperature vary, the two resonance peaks will change, and the RI and temperature could be measured simultaneously by monitoring the wavelength shifts of the two peaks. Experimental results show that the sensor has an RI sensitivity of 1174 nm/RIU in the RI range of 1.335–1.37 and a temperature sensitivity of −0.7 nm/°C in the temperature range of 30 °C–80 °C. In addition, the results show that the crosstalk between the two sensing channels of the proposed sensor is negligible. The parallel polished structure is helpful to develop the multiparameter measurement sensors, which has potential application prospects in the biochemical sensing fields.

Generative Adversarial Neural Networks Model of Photonic Crystal Fiber Based Surface Plasmon Resonance Sensor

Photonic crystal fibers (PCF) for specific applications are designed and optimized by both industry experts and researchers. However, the potential number of design combinations and flexible propagation features are offering a wide range of application areas, resulting in an exponential increase in the search space. This issue combined with the speed of the commonly used full vectorial finite element method (FV-FEM) simulators causes the task to take a significant amount of time. As stated in the previous works, artificial neural networks (ANN) can be employed to predict the result of numerical simulations much faster. However, there are two issues with the methods proposed previously: the required number of samples for training and the generality of these methods. In this article, we propose the use of generative adversarial networks (GAN) to augment the real dataset to train an ANN model. The experimental analysis suggested that the proposed combination not only accurately predicts the confinement loss even with limited amounts of data but also GAN can be used to improve existing methods in the literature. Moreover, the proposed system can also predict the confinement loss over a range of analytes and wavelengths in a completely new geometric configuration and generic enough not to require any additional tuning when used in a new dataset. This property is demonstrated by experimenting on an existing PCF dataset, which the proposed system surpassed the accuracy of the method proposed for it.

Titanium dioxide (TiO2) coated optical fiber-based SPR sensor in near-infrared region with bimetallic structure for enhanced sensitivity

A multimode optical fiber-based surface plasmon resonance (SPR) sensor is proposed and theoretically analyzed by using the finite element method (FEM) and transfer matrix method (TMM) based numerical simulations. A bimetallic structure of silver (Ag) and gold (Au) is used as SPR active material, followed by titanium dioxide (TiO2) layer. The TiO2 material is used as a dielectric to enhance the proposed sensor's performance with optimized thickness. The results show that the properties of the proposed sensor are highly dependent on the width of the metal and dielectric coatings, which allows the resonance wavelength tuning. For an aqueous solution of the analyte with a refractive index of 1.37 RIU, the maximum sensitivity of the optimized structure was found to be 14,340 nm/RIU, with a figure of merit (FOM) of 35.7 RIU−1 theoretically. The sensitivity of the sensor and FOM is improved on state of the art, ultimately opening new windows of study in the areas of chemical sensing.

Multianalyte sensing analysis with multilayer photonic crystal fiber-based surface plasmon resonance sensor

In this work, we proposed multianalyte multichannel Photonic Crystal Fiber (PCF)-based Surface Plasmon Resonance sensor with gold- and silver-doped plasmonic layers. The Full Vectorial Finite Element Method (FV-FEM) with perfectly matched layers (PML) are employed for numerical analysis of the proposed sensor. The key propagation features, such as confinement loss, resonance condition, resolution, and sensitivity of the proposed sensor, have been reported for all possible refractive index variations. According to the spectral sensitivity analyses, the average sensitivities for fixed RI values are obtained as 4100 nm/RIU and 3820 nm/RIU for Ch1 and Ch2, respectively. On the other hand, results for varying RI values are obtained as 3600 nm/RIU and 3700 nm/RIU for Ch1 and Ch2, respectively. Moreover, the maximum average sensitivity of proposed sensor reaches to 4250 nm/RIU for varying RI at Ch2 and 4200 nm/RIU for varying RI at Ch1.