Plasmonics最新文献

This paper introduces a biosensor based on graphene metasurfaces, designed for virus detection in the terahertz (THz) regime. The proposed sensor comprises four resonators arranged in a semicircular configuration, strategically engineered to achieve enhanced sensitivity and overall performance. Computational simulations using COMSOL Multiphysics version 6.2 were employed to optimize geometric parameters and analyze the sensor’s behavior. By integrating Au, SrTiO₃, graphene, and black phosphorus, the biosensor exhibits remarkable sensitivity to refractive index (RI) variations associated with various viruses. The maximum sensitivity demonstrated by the sensor is 4556 GHzRIU⁻¹. Other remarkable performance metrics include a figure of merit of 8.499 RIU⁻¹, a quality factor of 1.131, and a minimum detection limit of 0.149. Electric field distribution analysis reveals optimal absorption at 0.4 THz. Furthermore, the biosensor demonstrates the potential for 2-bit encoding applications. Compared to existing designs, the proposed biosensor offers significantly higher sensitivity for virus detection. The integration of advanced nanomaterials and metasurface design principles presents a promising avenue for rapid, label-free virus sensing, with potential applications in healthcare and biosecurity.

In this work, we present a surface plasmon resonance (SPR) based photonic biosensor for the detection and differentiation of healthy and infected brain tissues, including lesions, tumors, and malignant tissues. The biosensor design incorporates a BK-7 prism, silver (Ag), MXene (Ti₃C₂T_x), and graphene. Silver serves as the plasmonic material, coated on the prism’s flat surface to enhance plasmon generation, assisted by MXene and graphene for improved sensing performance. Extensive analysis and investigation have been conducted to leverage the unique characteristics of graphene and MXene in the design of this highly sensitive biosensor. The biosensor’s performance has been evaluated in terms of sensitivity, with remarkable results. The proposed biosensor demonstrates an exceptionally high sensitivity (S) of 240 (^circ)/RIU, detection accuracy of 0.1984 (^circ), and figure of merit (FoM) of 47.81/RIU. These findings confirm the biosensor’s reliability and effectiveness in accurately identifying various brain tumor tissues.

A photonic crystal fiber (PCF) sensor comprising two sensing channels for magnetic field and temperature measurements is proposed. In order to detect the magnetic field and temperature effectively, the two sensing channels of the proposed sensor are embedded with gold nanowires and filled with Polydimethylsiloxane (PDMS) and magnetic fluid (MF), respectively. Additionally, this configuration simplifies the fabrication process and eliminates some problems when plasmonic material is deposited in the inner or outer surface of PCF. The performance of the proposed sensor is numerically investigated by the finite element method (FEM). The optimal structural parameters have been determined by analyzing the loss curves and energy of the y-polarized core mode ultimately. Furthermore, the sensitivity is not particularly sensitive to the sizes of the cladding air holes, indicating the sensor has better manufacturing tolerance. The simulation results reveal the maximum magnetic field sensitivity is 238.4 pm/Oe at the magnetic field of 30–300 Oe, and temperature sensitivity is − 1103.6 pm/°C at the temperature of − 20–40 °C. The proposed sensor can detect sub-zero temperatures with a high magnetic field sensitivity. Given its low fabrication complexity and extensive detection range, this PCF-SPR sensor has potential applications in magnetic environments at low temperatures, such as geological exploration, marine environment monitoring, and so on.

The surface plasmon polariton (SPP) is an electromagnetic wave mode that occurs at the interface of a metal and a dielectric material. It possesses unique properties such as enhancing the strength of the electromagnetic field at the metal surface, achieving sub-wavelength focusing of light waves, and exhibiting low loss. Due to these characteristics, SPP holds great promise in various applications including super-resolution imaging, terahertz technology, biosensing, and optical communication. This paper proposes two Spoof SPP-based tri-band bandpass filters that replace the conventional sawtooth cell structure with a miniaturized labyrinth resonator structure. Upon investigating the dispersion characteristics of the resonators, we found that both resonator unit 1 and resonator unit 2 exhibit three modes, resulting in three notch points for each filter. Unlike most SPP-based structures, our design features a compact structure fed by a co-planar waveguide (CPW) without an added ground at the bottom, thereby reducing losses and improving efficiency. To achieve a smoother transition from CPW to the transmission structure, we utilize a segment of microstrip line structure synthesized by a logarithmic function. Both filters are of the same size, with dimensions totaling 192 mm × 42 mm. Based on our study, we have designed two filters with multiple notch points and have obtained good agreement between the simulation results and the actual test results.

Enhancing photon absorptance in ultrathin solar/thermophotovoltaic (STPV) cells is crucial for low-cost highly efficient cells. A complete study of power conversion enhancement, in a proposed ultrathin STPV cell, is presented here. It involves lead sulfide colloidal quantum dots (PbS-CQDs), a silver (Ag)-nano-pyramid design, aluminum nitride (AlN) crossed prisms as front texturization, with embedded Ag nanospheres, and a tantalum (Ta) film as a back reflector. By combining the three mechanisms of surface plasmon polariton (SPP), localized plasmons (LSPR), and magnetic polariton (MP) in the same structure, photon absorptance in the active PbS-CQDs layer is greatly improved. The suggested structure attained a highly active absorptance of over 80%, covering visible and near-infrared (0.30–1.77 µm). The short circuit current density is also evaluated under AM 1.5 solar illumination and various blackbody temperatures (T_B), with values of 48.90 mA cm⁻² and 6.93 mA cm⁻², respectively, corresponding to unprecedented power conversion efficiencies (PCEs) of 20.20% and 15.58%. The effects of metamaterial light management on PCE enhancement are discussed. Collectively, the findings show that the proposed hybrid cell is potentially useful in high-performance hybrid thermal and solar cells.

Graphical Abstract

Temperature and humidity sensors are applied in environmental monitoring, agriculture, the food industry, and biochemical detection. To enhance their sensitivity and efficiency, this work presents a temperature and humidity sensor that uses surface plasmon resonance (SPR) and photonic crystal fiber (PCF). The sensor comprises a hexagonal pattern of holes and two planes. On one side of the plane, a gold film coated with polydimethylsiloxane (PDMS) is used for temperature measurement, while on the other side, a gold film with polyvinyl alcohol (PVA) is used for humidity measurement. The finite element method is used to analyze the sensor’s sensing characteristics, revealing that its temperature sensitivity ranges from 20 to 90 ℃ at 3.82 nm/℃, while its humidity sensitivity ranges from 20 to 98% at 5.013 nm/%RH. Overall, this sensor can operate effectively in both temperature and humidity environments, simultaneously measuring both parameters.

This work presents the design and numerical simulation of a multilayered surface plasmon resonance (SPR) sensor incorporating borophene and germanium (Ge)-antimony (Sb) telluride (Te) (GST) as active plasmonic materials. The sensor design is modelled in two dimensions (2D) and exhibits a broad refractive index detection range, from 1 to 2.5 µm/RIU. The proposed design utilizes a top-analyte configuration, where the target analyte is placed directly on the sensor surface for interaction. Various metals like Ag (silver), Au (gold), Al (aluminium), and Cu (copper) are considered for investigation of the influence of the middle metal layer on the overall optical response. The GST layer is modelled as a two-state material, accounting for its amorphous (aGST) and crystalline (cGST) phases. It allows for exploring the sensor’s tunability based on the GST material’s phase state. Furthermore, comprehensive optimization and validation processes are conducted for various device parameters, including layer thicknesses, widths, and the type of metal employed. These optimizations aim to achieve optimal sensor performance regarding sensitivity and overall functionality. Notably, the simulations reveal distinct bandwidths and resonant regions for both aGST and cGST phases of the GST layer. In conclusion, this proposed sensor provides potential application in biomolecular and chemical testing due to its tunable characteristics and broad refractive index detection range.

This paper presents an innovative multifunctional wideband conformal metasurface structure using phase-changing vanadium dioxide. It consists of “quad dual-connected arrows-shaped VO₂ resonators” on an amorphous silicon dioxide (SiO₂) substrate backed with a 0.2-µm-thick gold layer. This unique design functions as a reflector and absorber offering a novel contribution in the terahertz frequency range. Each unit cell covers a 6-THz bandwidth from 5.6 to 11.6 THz with more than 90% absorptivity and reflectivity. For deeper insight, the paper also explores its circuit model, surface currents, and field distributions. Furthermore, this wideband absorber maintains its performance at incident angles up to 55°, showing polarization-insensitive behavior. The simulated absorptivity aligns well with the absorptivity extracted using an equivalent circuit model (ECM). Its outstanding performance makes it suitable for electromagnetic interference-EMC, biomedical, and stealth applications.

In this study, a D-type photonic crystal fiber (PCF) refractive index (RI) sensor based on surface plasmon resonance (SPR) is designed. The plasma material is silver (Ag), and the titanium dioxide (TiO₂) is selected to cover the silver film to protect silver from oxidation and enhance the SPR effect. This design enables the sensor to effectively detect the RI change of the analyte. Utilizing the finite element method (FEM), we elaborately researched and optimized various structural parameters and analyzed the influencing factors of the sensor performance. The operating wavelength range of the sensor is from 1000 to 2000 nm. In the RI sensing range of 1.345 to 1.405, the designed PCF sensor possesses an extraordinary maximum wavelength sensitivity of 32,000 nm/RIU, the outstanding figure-of-merit (FOM) of 584.59 RIU⁻¹, and a maximum resolution of 3.125 × 10⁻⁶ RIU. The results concise indicate that the proposed sensor exhibits predominant sensitivity and resolution to the changes of RI of analyte through the SPR effect. The sensor has significant advantages such as ultra-high sensitivity, small size, and low manufacturing complexity.

Here, the characteristics of hybrid plasmon modes of disk@ring nanoparticle were investigated by finite difference time domain simulation method. The change of the distance from the edge of the disk to the center of the ring, the change of the polarization angle, and the number of disks were considered as an asymmetry parameter in the research. The obtained results showed that two kinds of plasmon appear in near-infrared and visible regions, which are related to bonding and anti-bonding modes, respectively. This study can have potential applications in nano and biosensors in the detection of chemical species and threshold excitation of nanolasers in hybrid plasmonic wavelengths.