Plasmonics最新文献

CeO₂-doped V₂O₅ nanocomposites show promise for photodetector applications due to their improved optoelectronic characteristics. Using pulsed laser deposition at 300 mJ (energy) and 300 pulses, a series of n-V₂O₅:CeO₂/p-Si heterojunction visible light photodetectors was created as a function of the CeO₂ doping ratio (3, 6, and 9%). The structural properties of the prepared films, as represented by X-ray diffraction and scanning electron microscopy, indicated that the films were polycrystalline in nature. They exhibited an orthorhombic crystal structure along the preferred 001 direction, with the presence of two peaks associated with the doped material, which increased in intensity as the doping ratio increased. The films also exhibited spherical-like nanostructures across all of the prepared films. The prepared layers showed optical energy gaps of 2.45, 2.6, and 2.71 eV at doping ratios of 3, 6, and 9% of CeO₂, respectively. The manufactured devices also showed a well-oriented figure of merit at a very low bias voltage (0.5 V) as a function of wavelength and doping ratios. In detail, the prepared detector at 9%, which is the optimal value for the obtained results, demonstrated a responsivity of 58 μA/mW as a function of wavelength, in addition to a D* of 24 × 10¹⁷ Jones and an EQE of 120% achieved at light monochromatic (LED-525 nm) and incident light 100 mW/cm², while this observation was found to deteriorate at lower/higher wavelengths. The results showed that the response and recovery times were 0.80 and 0.77 s, respectively. The obtained results indicate that CeO₂ doping has a significant effect when added to V₂O₅, and both are attractive materials for high-performance PN photodetectors for industrial optoelectronic applications.

To enhance the sensitivity of temperature and humidity sensors, and eliminate response band overlap, this work proposes a temperature and humidity sensor that is based on surface plasmon resonance (SPR) and photonic crystal fiber (PCF) with an H-shaped structure. As a functional layer, titanium dioxide can significantly enhance the intensity of surface plasmon waves (SPW) and increase the effective sensing area. On one side of the H-shaped plane, a gold film coated with polydimethylsiloxane (PDMS) is used for temperature measurement, while on the other side, a gold film coated with agarose gel is used for humidity measurement. The finite element method (FEM) is employed to analyze the sensor’s performance, revealing that its responses occur in different frequency bands, enabling simultaneous measurement of temperature and humidity. The simulation results indicate that when the temperature ranges from 0 to 50 °C and the humidity ranges from 10 to 70%RH, the average sensitivities are − 3.13 nm/°C and 3.28 nm/%RH, respectively. This makes the proposed sensor have good application prospects in environmental monitoring, the food industry, medical sensing, and other fields.

Synthesis of nanoparticles (NPs) are pivotal in scientific and material-based research because of their unique physicochemical properties, which enable a wide range of applications in catalysis, electronics, biomedical engineering, and environmental remediation. Traditional methods for producing NPs often face challenges due to contamination, complex processing, and particle size and distribution control. To the best of our knowledge, this review is the first to focus on continuous-wave laser ablation in liquids (CWLAL)—an effective alternative for NP synthesis. Unlike conventional techniques, CWLAL is a straightforward and environmentally friendly approach for producing high-purity, ligand-free nanostructures with controlled features. This review provides insights into the mechanisms of NP formation via CW laser ablation as a primary tool, discusses studies on various materials used in NP synthesis, highlights recent advancements, and underlines the advantages of this method over pulsed laser techniques. The findings of this review emphasize the efficiency and versatility of CWLAL as a promising method for generating a diverse array of nanomaterials with significant potential across multiple applications.

A biosensor based on surface plasmon resonance (SPR) with triangular indentations is proposed to detect and identify five types of cancer cells, exhibiting refractive indices ranging from (varvec{1.368}) to (varvec{1.401}). This advanced biosensor features a multi-layer architecture comprising BK(varvec{7})/Ag/TiO(_{varvec{2}})/Al(_{varvec{2}})O(_{varvec{3}}) grating and operates within the optical telecommunication band (OTB) ((varvec{1260})–(varvec{1625}) nm). To enhance the biosensor’s performance, HeLa cells are employed as reference cells, and various parameters—including the angle of light incidence, the thickness of the Ag and TiO(_{varvec{2}}) layers, and grating specifications—are systematically analyzed to design a sensor with maximum sensitivity. The sensitivities achieved for the HeLa, Jurkat, PC-(varvec{12}), MDA-MB-(varvec{231}), and MCF-(varvec{7}) cells are (varvec{9208.33}), (varvec{9714.28}), (varvec{10,857.14}), (varvec{11,785.71}), and (varvec{12,214.28}) nm/RIU, respectively. Furthermore, the highest values for the sensor’s figure of merit (FoM) and quality factor (QF) are determined to be (varvec{122.14})/RIU and (varvec{14.53}). The highest FoM is recorded for MCF-(varvec{7}) cell detection, while the maximum QF is observed for HeLa cell detection. Analysis of the electric field distribution under resonant conditions reveals that the sensor exhibits a strong electric field with a penetration depth of 500 nm. A comparative analysis of the proposed sensor against previous designs indicates a substantial enhancement in various performance parameters, including sensitivity, FoM, and QF.

A photonic crystal fiber–surface plasmon resonance (PCF-SPR)-based refractive index (RI) sensor with a novel design is presented in this paper. This sensor detects the anomalies in the sample analyte by detecting the change in its RI. Silver (Ag) is used as a plasmonic material with a unique terracotta structure to sense the RI variations in the surrounding medium, also called an analyte or sample. A thin layer of titanium dioxide (TiO₂) measuring 10 nm is applied on top of the plasmonic material to prevent the oxidation of silver. The designed sensor detected a good range of analyte RI from 1.31 to 1.40 with the maximum amplitude sensitivity (S_A) and wavelength sensitivity (S_W) of 453.85 RIU⁻¹ and 25000 nmRIU⁻¹, respectively. Moreover, the amplitude resolution (R_A) and wavelength resolution (R_W) of the sensor are measured as low as 2.203 × 10⁻⁵ RIU and 4 × 10⁻⁶ RIU, respectively. However, we further investigated the figure of merit (FOM) of our proposed sensor and achieved a maximum FOM of 174.8 RIU⁻¹ which is enough for sensing. COMSOL Multiphysics is employed to accurately design and precisely evaluate key performance parameters of the sensor such as confinement loss, resonance wavelength, and sensitivity under various design conditions. The proposed unique terracotta structure, with a metallic strip for sensing on top, has simple and easy fabrication. Moreover, this RI sensor is useful in detecting a wide spectrum of applications falling in the range between 1.31 and 1.40, which include analytes like cancer cells; biomolecules: ribonucleic acid (RNA); deoxyribonucleic acid (DNA); glucose; proteins; carbohydrates, chemical analytes: alcohol; glycerol; organic acid; saline solutions; other water-based impurities along with pharmaceutical monitoring, environmental monitoring, and industrial analysis.

Biosensors have become essential tools in biomedical diagnostics, playing a crucial role across a wide range of applications, including disease development, virus detection, environmental monitoring, food safety, and various other diagnostic and therapeutic research areas. Plasmonic resonance has recently become a very promising method for biosensing applications, providing label-free and incredibly sensitive real-time analysis. The quick, real-time, label-free detection of biologically significant analytes is one application where plasmonic biosensing excels. Detecting tiny compounds at extremely low concentrations and creating small devices appropriate for point-of-care (PoC) diagnostics are still the main obstacles, nevertheless. This review highlights the latest trends and innovations in plasmonic biosensing, particularly focusing on new platforms that leverage the unique physicochemical properties and versatility of emerging materials. In addition to the well-established localized surface plasmon resonance (LSPR) technique, three major areas of development are discussed: chiral plasmonics, magnetoplasmonics, and quantum plasmonics. The review emphasizes recent advances in the design and fabrication of portable biosensing devices, particularly those operating with low losses across different frequency ranges, from the infrared to the visible spectrum.

A plasmonic sensor based on a Metal–Insulator-Metal waveguide integrated with a ring cavity, a semicircular rectangular cavity and a T-shaped cavity is proposed for multi-parameter sensing. Using the finite element method, the transmission spectrum and magnetic field distribution are analyzed. The independent tunability of three resonance modes is demonstrated by adjusting structural parameters and refractive indices. The sensor achieves sensitivities of 1350 nm/RIU, 1725 nm/RIU and 2450 nm/RIU for three modes, respectively. Moreover, leveraging the independent tunability, the sensor demonstrates simultaneous detection capabilities for voltage, concentration, and temperature with sensitivities of 8 nm/V, 3.5 nm/%, and -1.1 nm/℃. This work presents a highly efficient plasmonic sensor capable of detecting multiple parameters simultaneously, that offers potential applications in biomedical diagnostics and environmental monitoring.

We propose an anchor-shaped dual-channel photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) for simultaneous ultrawide-range detection of temperature and refractive index (RI) variations. The sensor features an asymmetric anchor-shaped cross-section with orthogonally polished semi-circular surfaces, selectively coated with gold and polydimethylsiloxane (PDMS) films. This structural configuration enables polarization-resolved SPR excitation, facilitating independent coupling of higher-order modes ({LP}_{11text{a}}^{x}) (x-polarized) and ({LP}_{11b}^{y}) (y-polarized) for dual-parameter sensing. The x-polarized channel, coated with both gold and PDMS, responds to changes in RI and temperature, while the y-polarized channel, coated solely with gold, targets RI sensing of another analyte. COMSOL-based simulations optimize structural parameters to ensure strong plasmonic coupling, effective mode confinement, and efficient higher-order mode excitation across both channels. The proposed sensor achieves a wide RI detection range from 1.21 to 1.44 and a wide temperature detection range from − 100 to 100 °C, with a maximum RI sensitivity of 14,500 nm/RIU and a temperature sensitivity of 4 nm/°C. These results demonstrate the sensor’s strong potential for practical applications, including real-time cancer cell detection, biochemical analysis, and multi-parameter monitoring in complex biological and chemical environments.

A dual-channel H-shape fiber (DCHF) sensor inlaid with a notched capillary is designed for the simultaneous detection of refractive index and temperature. The DCHF is fabricated by symmetrically etching two rectangular grooves on both sides of a multimode fiber (MMF) with a femtosecond laser and then embedding the DCHF into a notched capillary. By filling the analyte and thermo-sensitive liquid into the two rectangular grooves, a DCHF-based dual-parameter sensor is constructed for synchronous detection of the refractive index of the analyte as well as temperature. Furthermore, the Al wires are modified at positions closest to the core in both rectangular grooves to excite surface plasmon resonance (SPR) to enhance the sensitivity. The structural parameters of the DCHF-based dual-parameter sensor are systematically and comprehensively optimized to achieve superior sensing performance. Simulation results demonstrate that the sensor can synchronously detect refractive indexes in the range between 1.30 and 1.39 and temperature between 20 °C and 60 °C. The maximum refractive index sensitivity of 8,400 nm/RIU and maximum temperature sensitivity of 37.6 nm/°C represent a significant improvement over those of previously reported devices. Owing to the ease of analyte filling, non-interfering channels, high sensitivity, and simple fabrication process, the DCHF-based dual-parameter sensor has enormous potential in biochemical analysis, environmental monitoring, and other applications.