Surface Plasmon Sensor Research Articles

Detection of pathogens in water using long range surface plasmon resonance biosensor: Numerical investigation

This work presents a numerical demonstration for improving the imaging sensitivity of long-range surface plasmon (LRSPR) biosensors using the prism 2S2G/cytop/Cu/Gr (Graphene)/sensing medium (SM) configuration. In the suggested LRSPR biosensor, the imaging sensitivity is compared to that of the traditional surface plasmon sensor (tSPR) through numerical analysis. The proposed LRSPR sensor reaches 4655.7/RIU as its maximum imaging sensitivity for detecting E. coli bacteria. The maximum electric field intensity is found at the interface between the Cu/SM in the tSPR sensor and the Gr/SM in the proposed sensor. For pathogens detection such as pure-water (P.W.), Vibrio-Cholera (V.C.), Escherichia-Coli (E.coli), Bacillus-Anthracis (B.A.), and Enterococcus -aecalis (B.F), the penetration depth (PD) for the LRSPR sensor are 304.46 nm, 955.45 nm, 961.45 nm, 957.44 nm and 1050.7 nm. The LRSPR sensor's effectiveness in biosensing applications is further demonstrated by its figure of merit (FoM) for the detection of pathogens bacteria, which is 291.8/RIU (V.C), 781.5/RIU (E.coli), 59.28/RIU(B.A.) and 738.5/RIU (E.F.), respectively.

Deposition of a polymer thin film on a silver surface for surface plasmon sensing

We report a deposition method of a polymer thin film on the silver surface of a surface plasmon sensor for preventing sensitivity degradation in refractive index measurements due to the poor chemical stability of the silver. The deposition of a poly(methyl methacrylate) thin film with a ∼15 nm thickness was conducted by employing a spin coating technique along with a hydrophilicity enhancement of the silver surface using an atmospheric low-temperature plasma treatment. We experimentally verified the thickness by measuring the propagation constant of the surface plasmon. The measured propagation constants that showed the standard deviation at the order of 10−4 indicated microscopical uniformity. Furthermore, the reproducibility of thickness was experimentally verified.

Dual-channel surface plasmon sensor based on photonic crystal fiber for low refractive index detection

Dual-channel surface plasmon sensor based on photonic crystal fiber for low refractive index detection

Enhanced Fiber Long‐Range Surface Plasmon Sensing Enabled by Resonance Coupling to Surface Plasmon Polaritons

A tunable fiber optic (FO) long‐range surface plasmon (LRSP) sensor with strong coupling is developed and demonstrated theoretically in this article. The sensor consists of a square lattice array of Ag nanodisks resting on the FO end face. Utilizing nanodisks with small diameters leads to the pronounced excitation of two distinct and independent resonant modes: surface plasmon polaritons (SPP) and LRSP. A systematic investigation is performed to evaluate the sensing performance and capabilities of the sensor, focusing on its bulk and surface sensitivity. Significantly, the LRSP mode demonstrates high sensitivity and favorable linearity in response to refractive index (RI) changes, with an exceptionally high figure of merit (FOM). On the contrary, the SPP mode is regarded as an ideal self‐referencing mode due to its immunity to RI fluctuations. The enlargement of nanodisks diameters results in a swift redshift in the LRSP wavelength, leading to a strong coupling with the SPP mode. This coupling facilitates the transfer of electric fields within the SPP mode, promotes sensing capabilities, and enables the realization of dual‐channel sensing functionality. The occurrence of strong coupling phenomena along with the use of FO substrates provides an innovative option for achieving multifunctionality and miniaturization in sensor platforms.

Simulation research of localized surface plasmon sensor based on gold nanocone hexagonal array structure

The sensor based on gold nanocone hexagonal array structure was designed. Gold nanocone array was positioned above a gold film and separated by silica dielectric spacer layer. Finite-difference time-domain simulation was used to discuss theoretically the influence of gold film and dielectric layer thickness on the structure performance. The formation mechanism of three resonance peaks was studied through the electric field distribution. With the increase of the dielectric thickness, the absorption went upwards first and then went downwards. The refractive index sensitivity of the structure and figure of merit (FOM) at the dipole resonance peak can reach 450 nm/RIU and 4.3, respectively. At the peak caused by the plasmon resonance between the gold nanocone array and the gold film, the sensitivity is 275 nm/RIU while the FOM value is 18.3. The results provide a valuable insight into the application of metal nanoarrays in sensors.

Deposition of Polypyrrole-Carboxylated Multi-Walled Carbon Nanotube Nanohybrid Thin Film for Surface Plasmon Resonance Sensor

Immobilization of the enzyme is the main problem and critical factor in producing high selectivity and sensitivity of a surface plasmon sensor (SPR). This study is aimed at fabricating a uniform polypyrrole (PPy) - Carboxylated Multi-Walled Carbon Nanotube (MWCNT-COOH) nanohybrid film as a mediator, thereby enhancing the functional groups to attach and immobilize the enzymes for the SPR sensor. This nanohybrid thin film of PPy- MWCNT-COOH was electrodeposited on the surface of gold (Au)/chromium (Cr) by chronoamperometry using potentiostat at 0.7V for 5s and 10s. For the first time, the MWCNT-COOH is utilized and combined with conductive polymer PPy to investigate the SPR sensor at two different wavelengths which are 670 nm and 785 nm. The SPR curves and resonance angle are red-shifted and shallower when the time of electropolymerization increases. However, the resonance angle for the 785 nm optical wavelength is blue-shifted and the full-width-at-half-maximum (FWHM) is smaller compared to the 670 nm optical wavelength. The Fourier-transform infrared spectroscopy (FTIR) spectrum examination reveals the presence of the required functional groups from the fabricated PPy-MWCNT- COOH nanohybrid thin film to attach the enzyme immobilization in future work. In conclusion, the findings of this research can broaden exciting possibilities for the low-cost fabrication of promising SPR sensors at longer wavelengths.

The quality factor enhancement on gold nanoparticles film for localized surface plasmonic resonance chip sensor

Gold nanoparticles film as a part of an optical sensor is considered as active support in the development of specific chemical or biological biosensors optically. Well-organized gold nanoparticles can be prepared through inexpensive approaches where gold nanoparticles are easily obtained on a glass substrate. Herein, the authors propose a low-cost thermal synthesis of active plasmonic nanostructures on thin gold layers modified by a short annealing time (1 min and 15 min) at 550 °C and quickly followed by simple quenching. The results proved a good reproducibility of localized surface plasmon resonance (LSPR) optical responses with investigate the effects of modified thermal treatment on the morphology of gold thin films, the extinction LSPR spectra characteristics in the range between 350−1000 nm, and the quality factor (Q-factor) of the plasmonic resonance. The present findings that the proposed method gives evidence enhancement with the enrichment factor (EF-factor) values by about 310 %–460 %. We believe our study may have provided a strategy to enhance the fabrication of gold nanoparticles film based on plasmonic nanostructures for LSPR chip sensor applications.

Fabrication and Operation Analysis of a Surface-Plasmon Sensor Using a Nonpropagating Mode

Fabrication and Operation Analysis of a Surface-Plasmon Sensor Using a Nonpropagating Mode

Advances in Metallic-Based Localized Surface Plasmon Sensors for Enhanced Tropical Disease Detection: A Comprehensive Review

Advances in Metallic-Based Localized Surface Plasmon Sensors for Enhanced Tropical Disease Detection: A Comprehensive Review

A Modified Low-Cost Surface Plasmonic Sensor with Tunable Optical Actuation Angle Based on Micromachining Techniques Used by Microfluidics

A Modified Low-Cost Surface Plasmonic Sensor with Tunable Optical Actuation Angle Based on Micromachining Techniques Used by Microfluidics

Numerical Investigation on High-Performance Cu-Based Surface Plasmon Resonance Sensor for Biosensing Application.

This numerical research presents a simple hybrid structure comprised of TiO2-Cu-BaTiO3 for a modified Kretschmann configuration that exhibits high sensitivity and high resolution for biosensing applications through an angular interrogation method. Recently, copper (Cu) emerged as an exceptional choice as a plasmonic metal for developing surface plasmon sensors (SPR) with high resolution as it yields finer, thinner SPR curves than Ag and Au. As copper is prone to oxidation, especially in ambient conditions, the proposed structure involves the utilization of barium titanate (BaTiO3) film as a protection layer that not only preserves Cu film from oxidizing but enhances the performance of the sensor to a great extent. Numerical results also show that the utilization of a thin adhesive layer of titanium dioxide (TiO2) between the prism base and Cu film not only induces strong interaction between them but also enhances the performance of the sensor. Such a configuration, upon suitable optimization of the thickness of each layer, is found to enhance sensitivity as high as 552°/RIU with a figure of merit (FOM) of 136.97 RIU-1. This suggested biosensor design with enhanced sensitivity is expected to enable long-term detection with greater accuracy and sensitivity even when using Cu as a plasmonic metal.

Chitosan/polyaniline/graphene oxide-ferrocene thin film and highly-sensitive surface plasmon sensor for glucose detection

Chitosan/polyaniline/graphene oxide-ferrocene thin film and highly-sensitive surface plasmon sensor for glucose detection

Surface plasmon sensor for lead ion (Pb2+) detection using graphene oxide – Gold coated tilted fiber Bragg grating

In this study, the use of a surface plasmon sensor based on a gold-coated tilted fiber Bragg grating (Au-TFBG) functionalized with graphene oxide (GO) for the detection of lead ions (Pb2+) was demonstrated. To facilitate the modification of the Au-TFBG’s gold surface, cysteamine (Cys) was employed to form a self-assembled monolayer (Cys-SAM). This step was essential for binding the GO sheets on the Au-TFBG surface via the amine functional groups of Cys. Subsequently, the GO-COOH sheets were adsorbed onto the Au-linker surfaces. The sensor’s performance was assessed using several divalent metal ions, including Pb2+, Co2+, Cd2+, Ni2+, Zn2+, and Cu2+. Notably, the sensor exhibited the highest sensitivity for Pb2+. The measured sensitivity and limit of detection (LOD) were recorded at 0.018 dB/µM and 0.711 µM, respectively. Overall, the results demonstrate the potential of the GO-Au-TFBG sensor for sensitive and selective detection of Pb2+ ions, a capability that holds significant importance in environmental monitoring and industrial applications.

Graphene surface plasmon sensor for ultra-low-level SARS-CoV-2 detection.

Precisely detecting the ultra-low-level severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is crucial. The detection mechanism must be sensitive, low-cost, portable, fast, and easy to operate to tackle coronavirus disease 19 (COVID-19). This work proposes a sensor exploiting graphene surface plasmon resonance to detect SARS-CoV-2. The graphene layer functionalized with angiotensin-converting enzyme 2 (ACE2) antibodies will help efficient adsorption of the SARS-CoV-2. In addition to the graphene layer, ultra-thin layers of novel two-dimensional materials tungsten disulfide (WS2), potassium niobate (KNbO3), and black phosphorus (BP) or blue phosphorus (BlueP) used in the proposed sensor will increase the light absorption to detect an ultra-low SARS-CoV-2 concentration. The analysis presented in this work shows that the proposed sensor will detect SARS-CoV-2 as small as ∼1 fM. The proposed sensor also offers a minimum sensitivity of 201 degrees/RIU, a figure-of-merit of 140 RIU-1, and enhanced binding kinetics of the SARS-CoV-2 to the sensor surface.

Silver-Based Surface Plasmon Sensors: Fabrication and Applications.

A series of novel phenomena such as optical nonlinear enhancement effect, transmission enhancement, orientation effect, high sensitivity to refractive index, negative refraction and dynamic regulation of low threshold can be generated by the control of surface plasmon (SP) with metal micro-nano structure and metal/material composite structure. The application of SP in nano-photonics, super-resolution imaging, energy, sensor detection, life science, and other fields shows an important prospect. Silver nanoparticles are one of the commonly used metal materials for SP because of their high sensitivity to refractive index change, convenient synthesis, and high controllable degree of shape and size. In this review, the basic concept, fabrication, and applications of silver-based surface plasmon sensors are summarized.

Research Advances on Fiber-Optic SPR Sensors with Temperature Self-Compensation.

The fiber-optic surface plasmon resonance sensor has very promising applications in environmental monitoring, biochemical sensing, and medical diagnosis, due to the superiority of high sensitivity and novel label-free microstructure. However, the influence of ambient temperature is inevitable in practical sensing applications, and even the higher the sensitivity, the greater the influence. Therefore, how to eliminate temperature interference in the sensing process has become one of the hot issues of this research field in recent years, and some accomplishments have been achieved. This paper mainly reviews the research results on temperature self-compensating fiber-optic surface plasmon sensors. Firstly, it introduces the mechanism of a temperature self-compensating fiber-optic surface plasmon resonance sensor. Then, the latest development of temperature self-compensated sensor is reviewed from the perspective of various fiber-optic sensing structures. Finally, this paper discusses the most recent applications and development prospects of temperature self-compensated fiber-optic surface plasmon resonance sensors.

Black Phosphorous-Based Highly Sensitive Surface Plasmonic Sensor for Detection of Formalin

In the present work, a highly sensitive prism-based surface plasmon resonance (SPR) sensor for the detection of formalin using multilayer black phosphorous (BP) is proposed. Formalin, which is widely used as a preservative, can cause a variety of diseases, making its detection crucial. The transfer matrix method is utilized to compare and analyze the proposed structures of the SPR-based prism sensor in the Kretschmann configuration. The effect of prism materials (BAK3, BK7, SF10, SF11, and 2S2G), metals (gold, silver, copper, and aluminum), and 2-D materials (graphene, MoS2, WS2, and BP) on the performance of the sensor for formalin detection has been analyzed and discussed. The analysis of the impact of employing multilayer 2-D materials is carried out. Optimization of the thickness of the 2-D material is performed to achieve a structure that gives better sensitivity. The sensitivity achieved for structures with multilayer graphene, MoS2, and WS2 are 172.82°/RIU, 195.97°/RIU, and 218.04°/RIU, respectively. A highly sensitive structure for formalin detection is proposed with BK7, silver, and nine layers of BP. A sensitivity of 289.4565°/RIU and a detection accuracy (DA) of 0.3125/° are obtained. The limit of detection of the proposed sensor for different concentrations of formalin lies in the range of 3.45– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.56~ \mu $ </tex-math></inline-formula> RIU.

Surface plasmon resonance sensor for food safety

Surface plasmon resonance sensors have numerous applications in the discovery of poisonous gasses, water toxins, and the biomarkers of numerous infections. Surface plasmon sensors are a great candidate for future detecting stages due to their high sensitivity and fine resolution. A surface plasmon resonance sensor is also built for food safety using a Kretschmann setup with a gold coated prism. The setup was used to detect the analyte solution with concentrations 0%-3%. The sensor showed a good response and stability.

Double-layered side-polished ultra-highly sensitive photonic crystal fiber-based surface plasmonic refractive index sensor

Double-layered side-polished ultra-highly sensitive photonic crystal fiber-based surface plasmonic refractive index sensor

Strongly coupled surface plasmon resonance modes at both FF and SH in clusters of symmetrically distributed metallic nanospheres

Plasmonic nanoclusters play an important role in the rapid development of application of nanophotonics. In this article both the fundamental-frequency (FF) and second-harmonic (SH) responses of the complex nanoclusters (tetramer, hexamer, and octamer), constructed by coupled spherical plasmonic nanoparticles, are theoretically investigated. By using the multiple scattering algorithm, we present the comprehensive numerical analysis of the physical mechanisms pertaining to the linear and nonlinear coupled-plasmon modes, including ‘hot spot’ modes (HSMs) and ‘whispering-gallery’ modes (WGMs). Different from the symmetric coupling of plasmonic eigenmodes excited by the nanodimer, our analysis reveals that such coupled modes from the nanomultimers are the result of the ‘hybridization’ of symmetric and asymmetric coupling between adjacent dipole or higher-order multipole moments. Also, the remarkable enhancement as large as 3–4 orders of magnitude is achieved for the SH intensity when employing the plasmonic HSMs or WGMs at the FF. Interestingly, the nonlinear plasmonic HSMs and WGMs (the maximum Q up to 4800) can also be obtained by elaborately designing the system geometry. In addition, the resonant wavelengths of such coupled-plasmon modes can be linearly modulated within a broad range. These numerical results have potential applications in surface optical microscopy, plasmonic sensor and nanolaser.