Long-range Surface Plasmon Resonance Research Articles

Design of a highly sensitive and precise long-range surface plasmon resonance sensor for early detection of malaria

This manuscript presents an innovative Kretschmann configured for Long Range Surface Plasmon Resonance (LRSPR) sensor for malaria detection. It utilizes tungsten diselenide (WSe2) as a bio+molecular recognition element (BRE) layer to attach target analyte. The optimized sensor design demonstrates exceptional performance in detecting different malaria stages (Schizont with refractive index (RI) = 1.371, Trophozoite with RI = 1.381, and Ring with RI = 1.396) at a 633 nm wavelength. In comparison to conventional surface plasmon resonance (CSPR), the LRSPR biosensor exhibits a substantial improvement, a 6.67 to 10 times increase in detection accuracy (DA), an impressive 40 to 86.55 times enhancement in imaging figure of merit (IFOM), and a 6.0 to 8.66 times boost in imaging sensitivity (Simg.) for the sequential detection of different stages of malaria. COMSOL Multiphysics simulations highlight a deeper penetration depth (PD) of 258.71 nm, 276.85 nm, and 373.04 nm for the detection of Schizont, Trophozoite, and Ring stages, respectively.

Magnesium fluoride and black phosphorus mediated long-range surface plasmon resonance biosensor for enhanced sensing of SARS-CoV-2 virus

Magnesium fluoride and black phosphorus mediated long-range surface plasmon resonance biosensor for enhanced sensing of SARS-CoV-2 virus

A Dual-Channel Sensor Based on Long-Range Surface Plasmon Resonance for BSA Concentration and Temperature Measurement

A Dual-Channel Sensor Based on Long-Range Surface Plasmon Resonance for BSA Concentration and Temperature Measurement

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

Tantalum Disulfide (TaS2)–Based Symmetrical Long-Range Surface Plasmon Resonance Biosensor with Ultrahigh Imaging Sensitivity and Figure of Merit

Tantalum Disulfide (TaS2)–Based Symmetrical Long-Range Surface Plasmon Resonance Biosensor with Ultrahigh Imaging Sensitivity and Figure of Merit

A high-performance long-range surface plasmon resonance sensor based on the co-modification of carbon nanotubes and gold nanorods

In order to solve the problem that the sensitivity of the optical fiber surface plasmon resonance (SPR) sensor is limited and the full width at half maxima (FWHM) is greatly increased after modification of two-dimensional materials such as carbon nanotubes (CNTs), this paper proposes a Long-Range Surface Plasmon Resonance (LRSPR) Sensors co-modified by CNTs and gold nanorods. Gold nanorods were used to further enhance the sensitivity, and a simple and convenient method was used to excite the LRSPR by using low refractive index UV glue as a dielectric matching layer (DML). Compared with SPR sensor, the FWHM is reduced. The LRSPR sensor produced in this paper has a sensitivity of 5056.35 nm/RIU and a figure of merit (FOM) of 23.52 RIU−1, which are 150.64% and 24.38% higher than conventional SPR sensors, providing a method to achieve high sensitivity and FOM of the sensor. At the same time, the large specific surface area of CNTs and gold nanorods can also improve the biocompatibility of the sensor surface, which makes it have the potential of biosensing. In this paper, the use of UV glue as a DML to excite LRSPR is proposed for the first time.

Long-range surface plasmon resonance-based hollow fiber temperature sensor with ultrahigh sensitivity and tunable detection range.

A dielectric/Ag-coated hollow fiber (HF) temperature sensor based on long-range surface plasmon resonance (LRSPR) is proposed and experimentally demonstrated. The structural parameters, including the dielectric material and layer thicknesses, are optimized through comprehensive theoretical analysis to achieve the best performance. By filling it with a high refractive index (RI) thermosensitive liquid, the GK570/Ag-coated HF temperature sensor with optimal structural parameters is fabricated. Due to the high sensitivity of the LRSPR sensor and the optimized design, the fabricated sensor achieves a temperature sensitivity of 3.6∼20.5 nm/°C, which is almost the highest among the optical fiber temperature sensors based on surface plasmon resonance reported experimentally. Moreover, the detection range of the proposed sensor can be easily tuned up to 170°C by varying the RI of the filled thermosensitive liquid, and the sensor performance remains stable. Considering that most temperature sensors using polydimethylsiloxane have a fixed detection range, this is an outstanding advantage that could expand the application field of the optical fiber temperature sensor.

Black phosphorus mediated long-range SPR imaging sensor with ultrahigh imaging sensitivity, penetration depth and figure of merit

In this paper, we proposed a black phosphorus (BP) mediated long-range surface plasmon resonance (LRSPR) imaging sensor (Structure: 2S2G prism/Teflon/Ag/BP/Sensing medium) for refractive index (RI) sensing. MATLAB and COMSOL simulation software is used for analytical analysis of the proposed design at 633 nm characteristic wavelength. Use of Teflon dielectric buffer layer (DBL) and thin Ag film generates long-range surface plasmon polaritons (LRSPPs) at both interface of Ag film. BP layer is used as biorecognition element (BRE) layer for attachment of analytes due to its unique electrical, optical and electronic properties useful for sensing applications. The proposed sensor demonstrates maximum imaging sensitivity (29,971 RIU−1), detection accuracy (111 Deg.−1), angular figure of merit, FoMang. (2568 RIU−1), imaging figure of merit, FoMimg (810,027 RIU−1) and penetration depth, PD (1957 nm). Ultrahigh imaging sensitivity, FoMimg and micron size PD of the proposed sensor can be efficiently utilized for the deep analytes sensing even in smaller concentrations. Thus, BP mediated proposed RI sensor could provide potential application for micron size biomolecule sensing.

MXene-Mediated Long-Range Surface Plasmon Resonance (LRSPR) Sensor at Near-Infrared Wavelength

MXene-Mediated Long-Range Surface Plasmon Resonance (LRSPR) Sensor at Near-Infrared Wavelength

Enhanced upconversion luminescence using long-range surface plasmon resonance mode with prism coupler

In the study, we present the significant enhancement of the upconversion luminescence by taking advantage of long-range surface plasmon resonance mode. Compared with the reflection enhanced upconversion luminescence of Ag film, the intensity of upconversion luminescence enhanced by long-range surface plasmon resonance mode is improved 100 times. Additionally, the finite-difference time-domain simulation indicates that the incident light energy can concentrate in the upconversion nanoparticles doped dielectric layer at the long-range surface plasmon resonance mode, which the maximum electric field enhancement factor |E|2/|E0|2 can reach to 58. The experimental result shows that the upconversion luminescence enhancement is related to the thickness of doped Polymethylmethacrylate (PMMA) layer. Furthermore, due to the excited upconversion luminescence having high directionality, it is shown that the strong upconversion luminescence could be received at the specific angle.

Magnetically tunable ultralow threshold optical bistability by exciting LRSPR in InAs/graphene layers at the terahertz region.

With the experimental corroboration employing a transfer matrix method, an analytical observation of optical bistability using long-range surface plasmon resonance (LRSPR) through the external magnetic field is presented for a very low threshold value. The proposed analytical method has been verified with the reported experimental data provided by Liu etal. [Curr. Appl. Phys.29, 66 (2021)1567-173910.1016/j.cap.2021.06.003]. Now theoretical analysis is further extended in the proposed multilayered structure comprising an InAs layer sandwiched between two graphene layers, whose electromagnetic response at 2THz can be regulated by employing a magnetic field and may tune the optical bistability without modifying the geometry or the characteristics of the structure. The observed threshold intensity for the switch-up is 6.6615×104 W/c m 2 at 0.001T; thus, this analytical approach is able to achieve 2 orders lower threshold for magnetically tunable upswitching of the optical bistable process. This suggested magnetically adjustable optical bistable arrangement gives a possibility for the comprehension of optical logic gates, optic memory, opto-transistors, and switches at a low switching threshold due to extraordinary features of the composite layers due to local field amplification of the graphene layer.

Dual plasmonic modes in the visible light region in rectangular wave-shaped surface relief plasmonic gratings

Rectangular wave-shaped surface-relief plasmonic gratings (RSR-PGs) have been fabricated from a hybrid polymer by employing a simple nanoimprint photocuring lithography technique using a silicon template, followed by gold nanolayer metallization on top of the formed replica structure. By forming a one-dimensional (1D) plasmonic grating with a periodicity of approximately 700 nm, a reflectance spectral dip was experimentally observed in the visible light region, from 600 to 700 nm, with increasing incident angle from 45° to 60°. This dip can be associated with surface plasmon resonance (SPR) wave excitation, which is coupled with the diffraction order m = − 2. The calculations of reflectance spectra simulation using the rigorous coupled wave analysis (RCWA) method have also been carried out, resulting in the appearance of an SPR dip in the range of 600–700 nm, for incident angles in the range of 45°–65°, which agrees with the experimental results. Interestingly, these RSR-PGs show richer plasmon characteristics than the sine-wave-shaped plasmonic gratings. The experimental and spectral simulation results revealed two different plasmonic excitation modes: long-range SPR and quasi-localized SPR (LSPR). While the long-range SPR was formed above the ridge sections along the grating structure surface, the quasi-localized SPR was locally formed inside the groove. In addition, for RSR-PGs with a narrow groove section, the long-range SPR seems to be coupled with the periodic structure of the grating, resulting in the appearance of plasmonic lattice surface resonance (LSR) that is indicated by a narrower plasmon resonance dip. These characteristics are quite different from those found in the sine wave-shaped plasmonic gratings. The present results may thus provide better insights for understanding the plasmon excitations in this type of rectangular plasmonic grating and might be useful for designing their structure for certain practical applications.

Enhanced Long-Range Surface Plasmon Effect Based on Zr2CO2 MXene and MoSe2 Heterostructures for SPR Biosensors With High FOM

MXenes-based van der Waals heterojunction materials with excellent chemical stability and bioaffinity have been widely used in biosensing in recent years. We propose a new MoSe2@Zr2CO2 heterostructure as a long-range surface plasmon resonance (LRSPR) sensor based on the Kretschmann configuration from simulation and optimize the structure parameters algorithmically. First, we investigate the effect of different layers of MoSe2@Zr2CO2 heterojunction on the LRSPR wave. The results show that the optimal number of layers for heterogeneous layers is 18. Second, the effects of dielectric thickness and refractive index (RI) on sensitivity are investigated in depth, and optimized structural parameters are obtained. Finally, the effect of prisms with different refractive coefficients on the sensor performance is also discussed, and it is shown that prisms with lower refractive coefficients can effectively improve the sensitivity performance of the sensor. The sensor response performance to biomolecules is greatly enhanced due to the gain of light absorption and SPR. Compared with the conventional precious metal Au-based (50 nm) thin-film SPR sensor, the figure of merit (FOM) of the sensor is improved by a factor of 8.16, and higher sensitivity (92.48°/RIU) and quality factor (QF) (319.63 RIU−1) are obtained in the visible range.

Black Phosphorous and Cytop Nanofilm-Based Long-Range SPR Sensor with Enhanced Quality Factor

This numerical work proposes two novel designs of long-range surface plasmon resonance sensors (LRSPR) using two different coupling prisms. The performance analysis of the proposed sensor has been investigated using the performance parameters like quality factor ( Q ), detection accuracy (DA), sensitivity ( S ), and full-width half maximum (FWHM). The transfer matrix method (TMM) has been employed to compute reflectance. The role of the basic recognition element (BRE) has been played by the popular two-dimensional (2D) material, black phosphorus (BP), due to its many optoelectrical features. The maximum obtained values for Q , DA, and S are 3333.25 1 / RIU , 250 degree − 1 , and 13.33333 degree/RIU for 2S2G coupled sensor design and 3055.5 1 / RIU , 83.33 degree − 1 , and 36.66667 degree/RIU for BK7 coupled sensor design. The operating wavelength of 633 nm, followed by the principle of attenuated total reflection (ATR), has been employed to carry out the theoretical investigation.

High-sensitivity long-range surface plasmon resonance sensing assisted by gold nanoring cavity arrays and nanocavity coupling.

In many of the existing refractive index (RI) sensing works, only the shape and size of plasmonic structures are usually taken into account, while the parameters of spacer layers are ignored. In this publication, we explored the long-range surface plasmon resonance (LRSPR) and Fabry-Pérot resonance coupling effects of our proposed gold nanoring cavity array/spacer layer/Au mirror/glass substrate. Both the RI sensitivity and full width at half-maximum (FWHM) values were superior than those of conventional surface plasmon resonance substrates. We discussed the tunability of the RI sensitivity through changing the RI and thickness of the spacer layer. Then, under the optimized parameter conditions of the spacer layer, the geometry parameters (including size, gap and periodicity) of gold nanoring cavity arrays were tuned to optimize the best RI sensitivity. Finally, we broke the structural symmetry of a nanoring cavity to introduce Fano resonances into our system, and a high RI sensitivity and figure-of-merit (FOM) of 695 nm per RIU (refractive index unit) and 96.5, respectively, were achieved when the breaking angle θ was 30°. This study opens up many possibilities for boosting the FOM of RI sensing by taking into account the hybridization effects of localized surface plasmon resonance, LRSPR, and Fabry-Pérot and Fano resonances.

Low Dimensional Nanostructure-Assisted Long-Range Surface Plasmon Resonance Sensors With High Figure of Merit.

Long-range surface plasmon resonance (LRSPR) sensors have been extensively studied by virtue of their extremely narrow full width at half maxima (FWHM) characteristics, but their low sensitivity remains an important factor limiting the figure of merit (FOM), making the sensors have difficulties in detecting small refractive index changes accurately. To address this problem, this paper proposes and demonstrates a low dimensional nanostructure (Au nanospheres, WS2) assisted LRSPR sensor to achieve an effective enhancement of the sensor interfaced electric field and thus improve the sensitivity. The performance parameters of the two sensors are compared with the LRSPR sensor by finite element method analysis, and the results showed that the assistance of the low dimensional nanostructure has a positive effect on the sensor. The first refractive index sensing experiment of the WS2-assisted LRSPR sensor was realized with a 25.47% increase in sensitivity and a 7.13% increase in FOM simultaneously, and the Au nanospheres-assisted LRSPR sensor with a 29.23% increase in sensitivity and a 15.95% increase in FOM simultaneously. The introduction of low dimensional nanostructures provides a flexible and effective means of sensitization for LRSPR sensors, making the plasmon resonance sensors combine high sensitivity, narrow FWHM and high FOM, which have promising applications in biochemical sensing.

SARS-CoV-2 proteins monitored by long-range surface plasmon field-enhanced Raman scattering with hybrid bowtie nanoaperture arrays and nanocavities.

The identification of biomacromolecules by using surface-enhanced Raman scattering (SERS) remains a challenge because of the near-field effect of traditional substrates. Long-range surface plasmon resonance (LRSPR) is a special type of surface optical phenomenon that provides higher electromagnetic field enhancement and longer penetration depth than conventional surface plasmon resonance. To break the limit of SERS detection distance and obtain a SERS substrate with increased enhancement ability, a bowtie nanoaperture array was sandwiched between two symmetric dielectric environments. Then, an Au mirror was inserted to form a metal-insulator-metal configuration. Finite-difference time-domain simulations revealed that numerous hybrid modes can be provided by this novel configuration (denoted as long-range SERS [LR-SERS] substrate). In particular, the LRSPR mode can be excited and reach the maximum value through the regulation of the polarizations of the incident light and the geometrical parameters of the LR-SERS substrate. The optimized LR-SERS substrate was then applied to detect SARS-CoV-2 spike (S) and nucleocapsid (N) proteins. This substrate displayed ultralow detection limits of ∼9.2 and ∼11.3 pg mL-1 for the S and N proteins, respectively. Moreover, with the help of principal component analysis and receiver operating characteristic methods, our fabricated sensors exhibited excellent selectivity and hold great potential for the diagnosis of SARS-CoV-2 proteins in real samples.

Long-range SPR sensor employing platinum diselenide and cytop nanolayers giving improved performance

The designing of long-range surface plasmon resonance (LRSPR) biosensors using two-dimensional (2D) materials gained tremendous popularity due to their exclusive optoelectronic capabilities. Platinum diselenide (PtSe2) is one of the members of this 2D family, having unique properties. An LRSPR biosensor with cytop/Ag/PtSe2 configuration has been theoretically examined here. The transfer matrix method for TM mode was utilized in this study to compute the optical characteristics of the considered configurations for reflectance calculation. A new configuration of LRSPR biosensors based on BK7 prism/cytop/Ag/PtSe2 has been presented to improve detection accuracy and quality factor. The proposed design of the LRSPR biosensor gives maximum detection accuracy and a quality factor of 100 (ᵒ)−1 and 3400(RIU)−1 respectively with a sensitivity of 36.666 ᵒ/RIU. The proposed structure might be a biosensor for chemical detection, clinical diagnostics, and biological assessment.

Highly sensitive MXene-immobilized long range SPR sensor for biomolecule detection

In this article, a long-range surface plasmon resonance (LRSPR) sensor is proposed using the dielectric (Teflon)-metal (Silver)-Ti3C2Tx (MXene) layer for imaging sensitivity enhancement. MXene shows excellent properties, such as larger surface area, hydrophilic nature, high metallic conductivity, chemical stability, and strong biocompatibility for detection of biomolecules. The MXene layer is used here to improve imaging sensitivity and prevent unwanted silver oxidation. The proposed sensor takes advantage of the high adsorption efficiency of MXene for biomolecules and high resolution due to the LRSPR technique. Long-range SPPs are used to improve the imaging sensitivity, detection accuracy (DA), figure of merit (FoM) and penetration depth (PD) up to 4998/RIU, 12.5/°, 199.1/RIU and 546.65 nm, respectively, which are much higher than the present state of the art. The field intensity enhancement factor at the interface of the constituent layer of the proposed sensor and the conventional surface plasmon resonance (cSPR) sensor is also verified. The penetration depth (PD) of the field into the sensing layer for the LRSPR sensor is 2.5 times greater than that of the cSPR sensor. Thus, the proposed sensor offers potential benefits for sensing of large-sized biomolecules in the area of medical diagnostics.

Enhancing terahertz photonic spin Hall effect via optical Tamm state and the sensing application

The photonic spin Hall effect (PSHE), characterized by two splitting beams with opposite spins, has great potential applications in nano-photonic devices, optical sensing fields, and precision metrology. We present the significant enhancement of terahertz (THz) PSHE by taking advantage of the optical Tamm state (OTS) in InSb-distributed Bragg reflector (DBR) structure. The spin shift of reflected light can be dynamically tuned by the structural parameters (e.g. the thickness) of the InSb-DBR structure as well as the temperature, and the maximum spin shift for a horizontally polarized incident beam at 1.1 THz can reach up to 11.15 mm. Moreover, we propose a THz gas sensing device based on the enhanced PSHE via the strong excitation of OTS for the InSb-DBR structure with a superior intensity sensitivity of 5.873 × 104 mm/RIU and good stability. This sensor exhibits two orders of magnitude improvement compared with the similar PSHE sensor based on InSb-supported THz long-range surface plasmon resonance. These findings may provide an alternative way for the enhanced PSHE and offer the opportunity for developing new optical sensing devices.