Plasmonics最新文献

A highly sensitive plasmonic refractive index sensor using a circular ring resonator incorporating silver nanorods as defects are designed and investigated numerically in this article. The numerical investigation focuses on the impact of varying nanorod radius on the sensor’s performance. Results show that two distinct resonant dips in the transmittance spectrum are identified in the near-infrared region, where the second dip has found to have a heightened sensitivity which is particularly advantageous for chemical and biological sensing. The study reveals that increasing the nanorod radius enhances sensor sensitivity and results in a noticeable red shift in dip positions. The sensor attains a peak sensitivity of 2105 nm/RIU at nanorod radius of 22 nm. Furthermore, the proposed sensor is examined for its effectiveness in detecting adulteration in pure honey by sensing the change in resonance wavelength. The observations reveal the sensor’s capability to identify the percentage of externally introduced glucose and fructose in the honey by indicating shifts in resonance wavelength.

In this study, a compact plasmonic sensor that can generate dual Fano resonances is proposed. The structure is composed of a metal-insulator-metal (MIM) S-shaped waveguide with baffle, an analogous C-shaped resonator (ACR), and a T-shaped resonator with an annular cavity (TRAC). Employing the finite element method (FEM), the optical transmission characteristics of the structure are investigated. The results indicate that the dual Fano resonances arise from different resonators and can be independently tuned by altering the structural parameters of different resonators. Then, through adjusting the refractive index (RI) of the medium within the resonator in the range of 1.3–1.4, the RI sensing properties of the structure are also analyzed. The maximum RI sensitivity (S) and figure of merit (FOM) can be up to 2400 nm/RIU and 95.86 RIU⁻¹. Moreover, depending on the independence of the ACR and the TRAC, the sensor has efficient biochemical sensing characteristics and is used to achieve simultaneous determination of water-soluble vitamin B1 and vitamin C. The corresponding concentration sensitivities can be up to 500 nm·ml/g and 224 nm/C_vc, respectively. Consequently, the structure has significant potential for multifunctional biochemical sensing applications in high-density integrated circuits.

Plasmonic-based devices attracted considerable attention in the scientific community. However, noble metals provide less tunability to control the electromagnetic (EM) surface wave. Therefore, it is imperative to design dynamically tunable plasmonic devices. In this manuscript, a theoretical model is developed for a graphene-filled waveguide surrounded by uniaxial chiral material (UACM). The complex conductivity of graphene is modeled with the help of the eminent Kubo formula. By applying boundary conditions at the interface, the characteristic equation is derived to investigate the behavior of the normalized propagation constant for the proposed waveguide. The variation in normalized propagation constant under the different parameters of graphene such as chemical potential, relaxation time, number of layers as well as values of chirality for different cases of UACM, i.e., ({varepsilon }_{text{t}}) > 0, ({varepsilon }_{text{z}})> 0, ({varepsilon }_{text{t}}) < 0, ({varepsilon }_{text{z}}) < 0 and ({varepsilon }_{text{t}}) < 0, ({varepsilon }_{text{z}}>) 0 is analyzed in the THz frequency range. This study reveals that the normalized propagation constant is very sensitive when both longitudinal and transverse components of permittivity exhibit a negative sign (({varepsilon }_{text{t}}) < 0, ({varepsilon }_{text{z}}) < 0) as compared to the other two cases. It is observed that all three types of UACM have different cutoff frequency ranges. Field profile of UACM such as ({E}_{text{z}}) and ({H}_{text{z}}) also studied to confirm the existence of SPP. The present work holds promising potential to offer a new platform graphene-UACM-based plasmonic devices that can be utilized to fabricate waveguides that are dynamically tunable in different THz frequency regions.

The need for heating in household and industry is increasing, and this demand can be met with renewable energy using solar thermal absorbers. In the developing design construction, the three appropriate layers have been composed to perform a good solar absorber with different types of materials such as zirconium (Zr) as the resonator design, iron (Fe) used as the substrate section, and the ground titanium (Ti). With the help of a thin graphene layer addition, the current solar absorber improved the radiation observed and can able to extract the ultraviolet (UV) area, visible (V) regime, and also middle-infrared (MI) region. With the exact number of wavelengths and bandwidth expression, more than 97% of the rate has been extracted from 0.2 to 1.1 µm for 900-nm bandwidth, higher than 95% is 600-nm bandwidth between 0.1- and 1.7-µm wavelength, and the whole range of 2800-nm band rate is 90.43% respectively. To study the varied absorption rates in accentuation, the best four wavelengths of 0.2, 0.48, 0.81, and 1.21 µm are selected. To present the current work systematically, we divided the several sections into design and parameters, results and discussions, and conclusion. The current graphene-based absorber of Zr-Fe-Ti can be applied in warm builds, water heating systems, space heating, distillation, drying, and so on. Moreover, a large area of industrial heating process and artificial photosynthesis can be used.

In this study, we propose an enhanced ultra-high sensitivity prismatic surface plasmon resonance refractive index sensor. The core innovation of the sensor design lies in the integration of the two-dimensional nanomaterial black phosphorus with a corrugated silver layer. This synergistic combination significantly amplifies the interaction between the analyte and the sensing surface, thereby markedly enhancing the sensor’s performance. The influence of the corrugated silver layer and multi-layer black phosphorus on the sensing performance of the proposed sensor was analyzed using numerical simulations. By optimizing structural parameters, including the number of black phosphorus layers and the thickness and period of the corrugated silver layer, the sensor achieved ultra-high sensitivity and an exceptional figure of merit. Within the refractive index range of 1.330 RIU to 1.335 RIU, the sensor exhibited an average sensitivity of 1630°/RIU and a figure of merit of 217.333/RIU. Compared with previously reported prismatic surface plasmon resonance refractive index sensors, the proposed sensor exhibits significantly enhanced angle sensitivity. This sensor is particularly well-suited for detecting biomolecules, including the SARS-CoV-2 virus. It demonstrates substantial potential for applications in high-precision biomedical detection and medical diagnostics.

Plasmonic nanoantennas have earned significant acclaim for their remarkable ability to couple light from free space into sub-wavelength-sized structures and to enhance the confinement of the electric field. One of the most promising applications of plasmonics is refractive index sensing. To study the optical properties and near-field calculations of the nanoantenna, three-dimensional finite-difference time-domain (FDTD) simulations were conducted using commercially available Maxwell equation solvers, such as Lumerical software. A significant enhancement in electric field intensity and maximum absorption cross-section were observed when an array of plasmonic nanoantennas was used compared to a plasmonic nanoantenna dimer. The proposed device is used to sense changes in major air parameters such as carbon dioxide (CO₂) gas concentration and atmospheric pressure. Sensitivities as high as 488 nm/RIU and 500 nm/RIU, respectively, were achieved after analyzing both cases.

This paper presents a novel compact low pass filter (LPF) based on spoof surface plasmon polaritons (SSPPs) with ultra-wide out-of-band suppression. The design utilizes a single-layer PCB with metal gratings in a tilted slotted stub shape on the top layer. The device size is (0.75lambda _g times 0.12lambda _g) ((lambda _g) denotes the guided wavelength). A lumped equivalent circuit model is also provided. Simulated results demonstrate excellent passband performance and impressive ultra-wide out-of-band suppression. A fabricated prototype confirms simulation findings, showing 1.1 dB insertion loss at the center frequency, reflection coefficient below -10 dB in the passband, and over 30 dB out-of-band rejection beyond 38 GHz. The proposed compact SSPP LPF exhibits significant potential for applications in high-performance, miniaturized integrated circuits within the microwave frequency ranges.

Surface plasmon resonance sensing, which is based on photonic crystal fiber sensing technology, has a broad spectrum of applications in the detection of pharmaceuticals, environmental pollution, and food safety. This investigation proposes a photonic crystal fiber optic sensor with two cores and two holes to address the issue of limited sensor sensitivity. The high sensitivity of the sensor is optimized by the dual-channel design, which minimizes energy loss and maximizes the coupling efficacy in SPP mode by increasing the contact area of the measured liquid. Concurrently, the plasma resonance process generates an increased amount of energy due to the dual-core architecture. Simulation results show that the sensor has a maximum wavelength sensitivity of 21,500 nm/RIU and a maximum theoretical resolution as high as 4.878 × 10⁻⁷ RIU in the refractive index detection range of 1.33–1.43 and thus is expected to be applied in the field of hematology detection.

We propose a surface plasmon resonance (SPR) sensor based on the U-shaped photonic crystal fiber (PCF) coated with Au-TiO₂ layers, which can detect the refractive index (RI) of the analyte. We introduce elliptical air holes near the fiber core, which can break the symmetry of PCF structural and lead to a strong birefringence for achieving dual-polarization sensors. Besides, the TiO₂ layer not only enhances the adhesion of Au and quartz but also improves the SPR effect. By using finite element method (FEM) numerical analysis, geometrical parameters are optimized to enhance sensors’ performances, and dual polarization demonstrates superior performance in different detection ranges, expanding the range of analyte detection. Finally, simulation results show that the detection range under the Y-polarization (X-polarization) is 1.20–1.30 (1.36–1.43), with a maximum wavelength sensitivity of 10200 nm/RIU (5900 nm/RIU). This sensor offers broad RI detection range and high sensitivity, promising extensive applications in environmental and medical diagnostics.

In this paper, a plasmonic refractive index sensor is proposed for label-free sensing of biomolecules present in blood. The sensor design is conceptualized on a metal-insulator-metal waveguide setup consisting of a microring and a plus-shaped enclosed within a U-shaped resonator separated by a linear rectangular bus waveguide. The transmittance characteristics of the proposed design are studied using the finite difference time domain methodology. The transmittance curve results in quintuple Fano resonances with sensitivities of 1152.6 nm/RIU (refractive index unit), 1116.6 nm/RIU, 1182.2 nm/RIU, 1438.6 nm/RIU and 2109.7 nm/RIU at resonant wavelengths of 1.055 (mu )m, 1.146 (mu )m, 1.223 (mu )m, 1.494 (mu )m, and 2.12 (mu )m, respectively. Moreover, other performance parameters are also investigated including figure of merit, quality factor, and detection limit which comes out at a value of 91.3 (RIU^{-1}), 91.7, and 0.010, respectively. Furthermore, the sensor performance is investigated with respect to the detection of multiple biomolecules present in the blood. The highest sensitivity of 2180 nm/RIU is obtained with respect to analyte sensing.