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Sensitivity enhancement of SPR optical biosensor based on Graphene–MoS2 structure with nanocomposite layer
摘要： The optical plasmonic biosensors are an important research item in the field of bio-photonics. The graphene-molybdenum disulfide (MoS2) based hybrid structures are very useful in designing and fabrication of the high sensitive biosensors. In this paper, we designed hetero-structured Air/MoS2/Nanocomposite/MoS2/Graphene as an optical biosensor with high sensitivity. The proposed configuration for this Surface Plasmon Resonance (SPR) biosensor is Otto configuration. Herein, the enhancement sensitivity of this proposed SPR biosensor is investigated in different arrangement of layers. The influence of the refractive index of the coupling prism, the thickness of the nanocomposite layer, the constituent components of the nanocomposite layer and the number of the MoS2 layer is investigated and the optimal values is calculated for the biosensor with maximum sensitivity. The maximum sensitivity ～200°/RIU is achieved with six layers of MoS2 layer and a nanocomposite layer containing the gold nanoparticles and TiO2 as host dielectric.
关键词： Sensitivity,Biosensor,Nanocomposite,Graphene,Surface plasmon resonance,Molybdenum disulfide
更新于2025-09-09 09:28:46
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Reduced Graphene Oxide/Maghemite Nanocomposite for Detection of Lead Ions in Water Using Surface Plasmon Resonance
摘要： A prism-based surface plasmon resonance (SPR) sensor deposited with reduced graphene oxide/maghemite is presented for the detection of lead ions (Pb2+) in water. The SPR setup proposed followed the Kretschmann configuration with the installment of the nanocomposite integrated bilayer sensor chip onto the prism. For protection, the nanocomposite active layer was coated with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimidehydrochloride/N-hydroxysuccinimide. When the sensor was tested with different concentrations of Pb2+ in static water, the limit of detection was achieved at 0.001 ppm with a resonance angle shift of 0.184°. As an improvisation, a sample circulation design was adapted into the setup in order to increase the interaction rate between the sample and the sensing layer. This managed to improve the detection limit to 0.3 ppb.
关键词： surface plasmon,graphene,Optical sensing and sensors
更新于2025-09-09 09:28:46
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Integrating the plasmonic effect and p-n heterojunction into a novel Ag/Ag2O/PbBiO2Br photocatalyst: Broadened light absorption and accelerated charge separation co-mediated highly efficient visible/NIR light photocatalysis
摘要： Among several factors that influence the effectiveness of a semiconductor mediated photocatalysis, efficient charge separation and broadened light absorption are regarded as two of the most important parameters. Herein, a series of plasmonic p-n heterojunction Ag/Ag2O/PbBiO2Br photocatalysts with wide spectrum responses were successfully fabricated through a facile precipitation-calcination method. The obtained samples display exceptional photocatalytic performance for the degradation of tetracycline (TC), and the results reveal that the 10 wt% Ag/Ag2O/PbBiO2Br exhibits the optimal activity, which can efficiently decompose 84.4% of TC after 90 min of visible light irradiation. While under NIR light irradiation, the TC removal ratio can still reach 50.9% with 240 min. Besides, no significant deterioration in the degradation performance is observed even after four cycling runs. The photoactivity enhancement of Ag/Ag2O/PbBiO2Br can be credited to the synergistic effect between the local surface plasmon resonance (LSPR) effect of metallic Ag and the p-n heterojunction of Ag2O/PbBiO2Br, which not only greatly broadens the light utilization, but also remarkably accelerates the charge separation. The radical trapping experiments and the ESR measurements ascertains that %O2?, h+ and %OH play a critical role in the degradation of TC under visible light irradiation, while %O2? and h+ become the major reactive species in NIR light-driven reaction. According to the experimental results, the plausible reaction mechanisms for TC degradation over Ag/Ag2O/PbBiO2Br composite are proposed under both visible and NIR light irradiation. This work provides some guidance for rational construction of novel plasmonic p-n heterojunction photocatalysts to meet ever-increasing environmental requirements.
关键词： Surface plasmon resonance,Photocatalysis,P-n heterojunction,Tetracycline
更新于2025-09-09 09:28:46
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[IEEE 2018 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC) - Xuzhou (2018.7.21-2018.7.24)] 2018 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC) - A New Design for Spoof Surface Plasmon Polaritons Using Periodic Holes Etched on the Stripline
摘要： In this paper, a symmetrical ultrathin spoof surface plasmon polaritons (SSPPs) is realized based on the traditional coplanar waveguide (CPW), which can achieve multi-band high-efficiency transmission by employing the periodic holes etched on the middle stripline. Physical mechanism of the proposed SSPPs is explained by using the dispersion curves and electric field distributions. The measured results have a good agreement with the simulated ones, which indicate that the proposed SSPPs will be potentially very useful for microwave applications.
关键词： multi-band,spoof surface plasmon polaritons,high-efficiency transmission
更新于2025-09-09 09:28:46
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Shielding Spoof Surface Plasmon Polariton Transmission Lines Using Dielectric Box
摘要： Local leaky electromagnetic (EM) waves can impact the performance of the whole systems obviously due to the compact arrangement of integrated systems, including circuits based on spoof surface plasmon polaritons (SPPs). However, the widely used metallic shielding box in the traditional EM compatibility technology will affect the propagation of SPP modes dramatically. In this letter, we propose the double-layer dielectric shielding box made by materials with high permittivity, which can reduce leaky EM waves without affecting the transmission efficiency of SPP transmission lines (TLs). We demonstrate in simulation and experiment that the dielectric-shielded SPP TLs perform better in propagation than metallic-shielded SPP TLs. The effectiveness of the dielectric shielding boxes is investigated as well, and the calculated and measured results indicate that the double-layer dielectric structure can produce outstanding shielding effectiveness.
关键词： surface plasmon polaritons (SPPs),leaky waves,electromagnetic compatibility (EMC),metallic shielding,Dielectric shielding
更新于2025-09-09 09:28:46
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Mapping “Broken” Dark Modes Using Cathodoluminescence in a Scanning Electron Microscope
摘要： Dark plasmon modes are modes that lack a net dipolar character, and hence do not radiate efficiently. They possess a smaller spectral linewidth and longer lifetimes, making them attractive for many applications in sensing and for high-Q cavities. A focussed high-energy electron beam can be employed as a local, broad-spectrum excitation source, as the evanescent electric field associated with the fast electrons excites resonances in a polarizable material. The light that is radiated to the far-field can be collected in cathodoluminescence (CL), or the energy loss of the electrons can be measured in electron energy loss spectroscopy (EELS). The spatial resolution of these techniques in the scanning electron microscope (SEM) or scanning/transmission electron microscope (S/TEM) is typically limited by the spatial extent of the evanescent field (order of 10~nm depending on beam energy), making them ideal techniques for mapping the spatial distribution of plasmon modes. The energy lost to a dark mode can be detected in EELS, but since these modes are not radiative, in the strictest sense, these modes cannot be detected in CL. However, due to either inherent or introduced asymmetries in the structure, these dark modes acquire a net dipole resonance and do radiate. We performed hyperspectral CL on gold nanorod trimers fabricated using electron beam lithography using a beam energy of 30 keV and current of 500 pA (FEI Nova Nanosem). The CL was collected using a Delmic SPARC system equipped with an Andor Shamrock 303i spectrometer and Andor iVac spectral camera. We show the concurrent SEM images of a symmetric trimer and a trimer with an introduced asymmetry of an inter-trimer angle of 40 degrees. The trimers show two resonances, a high-energy symmetric mode and a low-energy mode composed of two degenerate dipole modes. We mapped these modes by mapping the average intensity between 350-500 nm and 600-700 nm, respectively. While it is clear that the trimer with broken symmetry has a prominent high-energy mode involving all three rods, the symmetric trimer appears to have enough inherent asymmetry to also display this mode. This inherent asymmetry can also be seen in the map of the dipole resonances. Dark modes that are “broken” by asymmetry acquire a dipolar component that allows them to be detected and mapped in CL. Hyperspectral mapping using CL is a powerful method for understanding the effect of nanoscale defects on plasmonic devices.
关键词： cathodoluminescence,plasmonic devices,Dark plasmon modes,scanning electron microscope,hyperspectral mapping
更新于2025-09-09 09:28:46
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Ultrathin tungsten bronze nanowires with efficient photo-to-thermal conversion behavior
摘要： In this work, we describe a simple one-step solvothermal method to synthesize ultrathin quaternary tungsten bronze nanowires (QTBNWs). In addition, a series of alkali metal-doped QTBNWs can be prepared by simply changing the type of starting alkali carbonate and tungstate. The as-synthesized QTBNWs exhibits strong near-infrared (NIR) rays absorption, high visible light transmission and excellent photo-to-thermal conversion behavior, which are superior to those of tungsten bronze nanorods and ternary TBNWs. And its excellent photothermal performance should be attributed to great localized surface plasmon resonances (SPR).
关键词： solvothermal method,photo-to-thermal conversion,near-infrared absorption,ultrathin tungsten bronze nanowires,surface plasmon resonances
更新于2025-09-09 09:28:46
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Surface plasmon induced atom localization in a tripod-type four level atomic system
摘要： We demonstrate the phenomenon of atom localization using surface plasmon polariton absorption/dispersion spectrums. A single and double localized peaks are measured on the absorption/dispersion spectrums of surface plasmon polariton at di?erent parameters and directions of propagation of the control ?elds. We show localized peaks with ～ 80% probability on dispersion spectrum and 50 % probability on the absorption spectrum. The localized peaks observed are shown to depend on strength of the control ?eld and the electrical conductivity.
关键词： surface plasmon polariton,atom localization,electrical conductivity,control ?elds,absorption/dispersion spectrums
更新于2025-09-09 09:28:46
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Wide-Angle Beam Scanning Leaky-Wave Antenna Using Spoof Surface Plasmon Polaritons Structure
摘要： This paper proposes a wide-angle beam scanning leaky-wave antenna (LWA) fed by a novel spoof surface plasmon polaritons (SSPP) transmission line (TL). In the proposed LWA, circular metallic patches are periodically loaded on both sides of the SSPP TL alternately, and convert guided waves into radiating waves. The transmission characteristics of the proposed SSPP TL are analyzed, and the transmission characteristics and radiation patterns of the proposed LWA are simulated and measured. The simulated and measured results show that the proposed LWA provides approximately 12.5 dBi of radiation gain within a frequency range of 8–24 GHz, and a beam scanning range of 90? from forward to backward continuously by increasing the feeding frequency. The proposed LWA, based on a novel SSPP TL, has advantages of single-layer conductor, continuous wide-angle beam scanning, and high gain especially at the broadside direction, which are dif?cult realize using conventional LWAs.
关键词： beam scanning,spoof surface plasmon polaritons (SSPP),wide-angle,leaky-wave antenna (LWA)
更新于2025-09-09 09:28:46
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Optical sensing platform for colorimetric determination of silver nanoprisms and its application for hydrogen peroxide and glucose detections using a mobile device camera
摘要： Silver nanoprisms (AgNPrs) have a unique localized surface plasmon resonance, resulting in strong absorption and scattering within the visible light region. In this work, we propose the image acquisition from colloidal solutions of AgNPrs using a combination of transmitted and scattering lights. The developed measurement technique could be carried out by separately recording transmitted and scattering images of the solutions, using a mobile device camera prior to calculation of empirical absorption value (IA). IA value of green for AgNPrs solutions was found in agreement with the absorption spectra obtained using a conventional spectroscopic technique. This technique was utilized for the quantifications of hydrogen peroxide and glucose. The good linearities between ΔIA and those typical analytes were observed. The limit of detection for typical biosensor of glucose was 19.8 μM. As such, we expect the methodology herein developed for hydrogen peroxide and glucose determinations by means of monitoring the color change of transmitted and scatting images from solutions, to contribute to the development of simple, rapid, and reliable detection systems to be further applied in biochemical analysis and clinical diagnosis, as well as in household biosensor applications.
关键词： silver nanoprisms,glucose sensor,hydrogen peroxide sensor,localized surface plasmon resonance,colorimetric method
更新于2025-09-09 09:28:46