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Plasmonic Nanocavity Metasurface Based on Laser-Structured Silver Surface and Silver Nanoprisms for the Enhancement of Adenosine Nucleotide Photoluminescence
摘要： A reliable photoluminescence (PL) spectroscopy and imaging of biomolecules at room temperature is a challenging and important problem of biophysics, biochemistry, and molecular genetics. A unique effect of strong plasmonic enhancement of the PL by metal nanostructures is one of the most effective approaches for this purpose. The highest enhancement is provided by metal nanostructures with densely packed sharp tips, periodically arranged metal nanostructures, and plasmonic cavities. All of these features have been realized in the plasmonic cavity metasurface based on the silver (Ag) laser-induced periodic surface structure and Ag triangular nanoprisms studied in the present work. The strong plasmon-enhanced PL of 5′-deoxyadenosine monophosphate deposited on such metasurfaces has been revealed at room temperature. The observed enhancement of more than 1000-fold has been interpreted as a result of synergetic action of the generation of a high concentration of hot spots near the sharp edges of the laser-induced surface structure and nanoprisms together with excitation of the collective gap mode of the cavity due to strong near-field plasmonic coupling. Correspondingly, the plasmonic cavity metasurfaces consisting of metal laser-induced periodic surface structures and nonspherical metal nanoparticles with sharp edges have been shown to be crucial for the highly sensitive detection and imaging of biomolecules at room temperature without consuming any dye labels.
关键词： hot spots,plasmon gap mode,plasmonic metasurface,near-field coupling,nucleotide photoluminescence enhancement
更新于2025-11-19 16:46:39
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Ultrathin Circular Polarimeter Based on Chiral Plasmonic Metasurface and Monolayer MoSe2
摘要： Two-dimensional materials are ideal platforms for intriguing physics and optoelectronic applications because of their ultrathin thicknesses and excellent properties in optics and electronics. Further studies on enhancing the interaction between light and two-dimensional materials by combining metallic nanostructures have generated broad interests in recent years, such as enhanced photoluminescence, strong coupling and functional optoelectronics. In this work, an ultrathin circular polarimeter consisting of chiral plasmonic metasurface and monolayer semiconductor is proposed to detect light with different circular polarization within a compact device. A designed chiral plasmonic metasurface with sub-wavelength thickness is integrated with monolayer MoSe2, and the circular-polarization-dependent photocurrent responses of right and left circularly polarized light for both left- and right-handed metasurfaces are experimentally demonstrated. The photoresponse circular dichroism is also obtained, which further indicates the remarkable performance of the proposed device in detecting and distinguishing circularly polarized light. This design offers a great potential to realize multifunctional measurements in an ultrathin and ultracompact two-dimensional device for future integrated optics and optoelectronic applications with circularly polarized light.
关键词： circular polarimeter,chiral plasmonic metasurface,MoSe2,photocurrent responses,two-dimensional materials
更新于2025-09-23 15:21:01
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Low-cost and high sensitivity glucose sandwich detection using a plasmonic nanodisk metasurface
摘要： Glucose detection using Surface-enhanced Raman scattering (SERS) spectroscopy has aroused considerable attention due to its potential in the prevention and diagnosis of diabetes as a result of its unique molecular fingerprinting capability, ultrahigh sensitivity and minimal interference from water. Despite numerous solutions to improve the sensitivity of glucose detection, the development of a new SERS-based strategy to detect glucose with high sensitivity and low-cost is still required. In this study, we propose a simple and sensitive SERS-based plasmonic metasurface sensing platform for a glucose sandwich assay using self-assembled p-mercapto-phenylboronic acid (PMBA) monolayers on a gold nanodisk (Au-ND) metasurface and synthesized silver nanoparticles (Ag NPs) modified with a mixture of p-aminothiophenol (PATP) and PMBA. The localized near-field of the proposed plasmonic metasurface is markedly enhanced due to the coupling between the Au-ND and Ag NPs, which greatly improves detection sensitivity. The experimental results show that SERS signals of the glucose assay are significantly enhanced by more than 8-fold, in comparison with the SERS substrate of smooth Au film and Ag NPs. Moreover, the plasmonic metasurface-based glucose sandwich assay exhibits high selectivity and sensitivity for glucose over fructose and galactose. The developed plasmonic metasurface sensing platform shows enormous potential for highly sensitive and selective SERS-based glucose detection and opens a new avenue for scalable and cost-effective biosensing applications in the future.
关键词： Surface-enhanced Raman scattering (SERS),glucose detection,gold nanodisk (Au-ND),p-mercapto-phenylboronic acid (PMBA),p-aminothiophenol (PATP),silver nanoparticles (Ag NPs),plasmonic metasurface
更新于2025-09-23 15:19:57
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Polarization-Controlled Plasmonic Structured Illumination
摘要： Structured light in the subwavelength scale is important for a broad range of applications ranging from lithography to imaging. Of particular importance is the ability to dynamically shift the pattern of the fields, which has led to the development of structured illumination microscopy. Further extension of structured illumination to plasmonic systems has enabled imaging beyond diffraction limit. However, structured illumination usually requires complicated optical setups entailing moving mechanical parts. Here a polarization tunable structured plasmonic fields (SPF) is proposed and experimentally demonstrated. The SPF is formed by surface plasmon interference (SPI) generated by a fishbone-shaped metasurface on a thin gold film. Importantly, the SPF can be continuously shifted by merely varying the linear polarization state of an incident beam. The precise control of the fringes of structured illumination and elimination of mechanical control will have great potential in subdiffractional imaging for practical applications.
关键词： Plasmonic,metasurface,structured illumination,subdiffractional imaging
更新于2025-09-19 17:13:59
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Enhanced terahertz emission bandwidth from photoconductive antenna by manipulating carrier dynamics of semiconducting substrate with embedded plasmonic metasurface
摘要： In this article, we demonstrate a technique to enhance the Terahertz (THz) emission bandwidth from photo-conductive antenna (PCA) based on semiconducting substrates by manipulating the surface carrier dynamics of the semiconductor. Bandwidths in PCAs are limited by the decay of the photogenerated charge carriers, which in case of SI-GaAs is in the orders of 50 picoseconds. We show, with an embedded design of plasmonic meta-surface in the photoconductive gap of a PCA, it is possible to enhance the emission bandwidths by more than 50 percent. This is due to the fact that these nano-structures act as local recombination sites for the photogenerated carriers, effectively reducing the carriers’ lifetime. Additionally, the defect sites reduce the terminal current, thereby reducing the Joule heating in the device. Furthermore, the meta-surface also facilitates higher in-coupling of the exciting infrared light on to the PCA, thereby increasing the optical-to-THz conversion efficiency of the device.
关键词： carrier dynamics,plasmonic metasurface,bandwidth enhancement,photoconductive antenna,Terahertz
更新于2025-09-16 10:30:52
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Broadband multi-resonant circular dichroism in metal-VO2 hybrid dagger-like plasmonic structure for switching application
摘要： Metallic and metal-VO2 hybrid dagger-like novel chiral plasmonic structure is proposed and demonstrated numerically using finite difference time domain (FDTD) computation to realize broadband multi-resonant circular dichroism (CD). CD switching is realized in the hybrid system that can be actively controlled externally. Dagger-like structure is considered where asymmetry is introduced in both the arms of a dagger structure to break in-plane rotational symmetry making the structure in-planar chiral. Multi-resonant broadband CD between visible to infrared frequencies is observed in pure asymmetric metallic dagger-like structure (MDLS) made of gold, as well as, in asymmetric metal-VO2 hybrid dagger-like structure (MVHDLS). Interestingly, multi-resonant CD in MVHDLS vanishes completely when VO2 phase changes from semiconducting to metallic phase. Dynamic control of VO2 phase externally enables us to realize CD switching action in MVHDLS. The proposed structure opens up the possibility of switching based plasmonic and photonic CD applications.
关键词： Modeling and simulation,Novel metal-VO2 hybrid dagger-like structure,Circular dichroism and its switching,Plasmonic metasurface
更新于2025-09-16 10:30:52
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[IEEE 2019 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD) - Ottawa, ON, Canada (2019.7.8-2019.7.12)] 2019 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD) - Numerical Analysis of Quantum Plasmonic Metasuraface by Time-Dependent Density Functional Theory
摘要： We theoretically investigate optical properties of a quantum plasmonic metasurface composed of metallic nanoparticles that are arranged in a two-dimensional matrix form with a sub-nanometer gap. We employ a time-dependent density functional theory approach to calculate optical properties of the metasurface. They show characteristic features at gap distance smaller than 0.4 nm due to the tunneling currents that flow through the gaps.
关键词： optical properties,tunneling currents,time-dependent density functional theory,quantum plasmonic metasurface
更新于2025-09-12 10:27:22