- 标题
- 摘要
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- 实验方案
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Modeling of 1D Au plasmonic grating as efficient gas sensor
摘要： Gas-sensor reported here consist of a sensingchip of a metallic grating designed on gold (Au) film over a glass substrate which has been modelled using finite element analysis (FEA). The Au is layered in the form of horizontal nano-strips with a periodic nano-sized gap known as slit-width. The transverse magnetic (TM) light illuminates the metallic films from substrate side at normal incidence. The transmission loss spectrums have been extracted for 0th order diffraction for different physical interpretations. The several combinations of periodicity and slit width have been optimized by taking slit width as half of periodicity. The refractive index sensitivity achieved at optimal geometrical parameters is noteworthy and it is reported to be 599 (nm/RIU) at a spatial period of 660 nm. The novel theoretical results has been supported by far field and near field analysis. The design suggested in this report is important becuase of the wavelength range that lie in the visible region where most of the real life spectrometers works. Such sensors can be applicable in industries for detection of toxic gases and harmful metallic pieces in atmosphere.
关键词： Resonance,Gas Sensor,Surface Plasmons resonance,Finite Elemental Analysis (FEA),Sensitivity
更新于2025-09-12 10:27:22
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Graphene’s photonics and optoelectronics properties – A Review
摘要： Due to its remarkable electrical and optical properties, graphene continues to receive more and more attention from researchers around the world. An excellent advantage of graphene is the possibility of controlling its charge density, and consequently, the management of its conductivity and dielectric constant, among other parameters. It is noteworthy that the control of these properties enables the obtaining of new optical/electronic devices, which would not exist, based on conventional materials. However, to work in this area of science, it is necessary a thorough knowledge regarding the electrical/optical properties of graphene. In this review paper, we show these graphene properties very well detailed.
关键词： Absorbance (78.20.-e),Conductivity (78.20.-e),Substrate (78.40.Fy),Reflectance (78.20.-e),Surface plasmons polaritons (73.20.Mf),Transmittance (78.20.-e),Dispersion relation (11.55.Fv),Dielecric constant (31.15.es)
更新于2025-09-12 10:27:22
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A Tunable Dual-Band and Polarization-Insensitive Coherent Perfect Absorber Based on Double-Layers Graphene Hybrid Waveguide
摘要： A suspended monolayer graphene has only about 2.3% absorption rate in visible and infrared band, which limits its optoelectronic applications. To significantly increase graphene’s absorption efficiency, a tunable dual-band and polarization-insensitive coherent perfect absorber (CPA) is proposed in the mid-infrared regime, which contains the silicon array coupled in double-layers graphene waveguide. Based on the FDTD methods, dual-band perfect absorption peaks are achieved in 9611 nm and 9924 nm, respectively. Moreover, due to its center symmetric feature, the proposed absorber also demonstrates polarization-insensitive. Meanwhile, the coherent absorption peaks can be all-optically modulated by altering the relative phase between two reverse incident lights. Furthermore, by manipulating the Fermi energies of two graphene layers, two coherent absorption peaks can move over a wide spectrum range, and our designed CPA can also be changed from dual-band CPA to narrowband CPA. Thus, our results can find some potential applications in the field of developing nanophotonic devices with excellent performance working at the mid-infrared regime.
关键词： Surface plasmons,Graphene,Absorption
更新于2025-09-12 10:27:22
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Gain‐Assisted Active Spoof Plasmonic Fano Resonance for High‐Resolution Sensing of Glucose Aqueous Solutions
摘要： Fano resonance has received much attention in recent years due to its promising applications in surface enhanced phenomena, sensing, and nonlinear optics. However, it is challenging to achieve both high quality (Q) factor and high intensity using the Fano resonance. Different from active switching/tuning of plasmonic Fano resonances, gain-assisted active spoof plasmonic Fano resonance is for the first time proposed to enhance both the Q factor and resonance intensity significantly, in which a subwavelength amplifier chip is incorporated into a passive plasmonic structure composed of two stacked corrugated metal rings. Experimental results show that the Q factor of the Fano resonance is increased from 49 to 2802, and the resonance intensity is improved from 19.89 to 37.42 dB. The high performance of the active plasmonic structure makes the limit of detection reach to 10 mg dL?1, and thus the minute change of glucose aqueous solutions has been successfully detected.
关键词： active plasmonic Fano resonance,localized surface plasmons,metamaterials
更新于2025-09-12 10:27:22
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Analysis of Plasmonic Gold Nanostar Arrays with the Optimum Sers Enhancement Factor on the Human Skin Tissue
摘要： We analyze the performance of the surface-enhanced Raman spectroscopy (SERS) substrate based on high-density gold nanostar nanoparticle (GNS) arrays assembled on the gold film and embedded in the human skin tissue as a surrounding medium. A self-assembled monolayer (SAM) of 3-aminopropyltriethoxy silane (APTES) is used for immobilizing GNSs on the Au film. The GNS–Au film and GNS–GNS coupling in the gap regions and also the GNSs interparticle coupling at their branches are observed, so the GNS arrays show more field enhancements and the sensitivity of the GNS sensor can be increased further. When the SERS substrate based on the GNS arrays is excited by a 785-nm laser line, a maximum enhancement factor (EF) of 109 is observed. It is demonstrated that the normalized EF depends on the geometry of the GNSs, the thickness of the Au film, and the separation distance between the cores of the GNSs.
关键词： thin films,spectroscopy,biomaterials,tissue diagnostics,nanostars,surface plasmons,plasmonics
更新于2025-09-12 10:27:22
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Dual-color near-field imaging by means of thin-film plasmonic waveguide with precise beam control of multiple wavelengths
摘要： We describe an improved optical beam control technique combined with a waveguide probe for imaging optical near-field using multiple wavelengths. The beam control technique varies the incident angle of pseudocollimated beams whose spot diameter is ～10 μm such that it is equal to an arbitrary angle with ～0.03○ precision and the beam position to ～0.1 μm precision. This helps resonantly excite surface plasmons using visible 660 nm and near-infrared 850 nm on an ～10 μm width three-dimensional microwaveguide. We demonstrate the operation of this system by imaging the optical near-field and capturing the interference of surface plasmons in a gold microstructure. This system achieved dual-color imaging of the optical near-field of different modulation frequencies with submicrometer lateral spatial resolution.
关键词： surface plasmons,optical beam control,multiple wavelengths,dual-color imaging,submicrometer lateral spatial resolution,waveguide probe
更新于2025-09-12 10:27:22
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Doubly-resonant plasmonic hot spot-exciton coupling enhances second harmonic generation from Au/ZnO hybrid porous nanosponges
摘要： We introduce zinc oxide (ZnO) functionalized porous gold nanoparticles which exhibit strong second harmonic (SH) emission due to an efficient coupling of localized surface plasmons to ZnO excitons. The nanosponges are perforated with a random network of 10-nm sized ligaments, localizing plasmons in a high density of hot spots. We use a broadband, few-cycle ultrafast laser to probe coherent nonlinear emission from individual bare gold and ZnO-functionalized sponges. While the third harmonic spectrum of the hybrid particles redshifts with respect to that of bare gold sponges, a distinct blueshift is seen in their SH spectra. SH emission around 390 nm, slightly below the ZnO band gap, is enhanced by ten times. We attribute this to doubly-resonant plasmon-exciton interactions: the laser drives nanosponge plasmon hot spot resonances and this locally enhanced field induces two-photon excitation of localized ZnO excitons. This opens a path towards the design of efficient coherent nonlinear optical sources by combining randomly-disordered nanoantennas with semiconductor gain materials.
关键词： exciton-plasmon coupling,Surface plasmons,third harmonic generation,zinc oxide,disordered nanoantennas,plasmon localization,nonlinear optics
更新于2025-09-12 10:27:22
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Impact of silver nanogratings for enhanced light absorption in plasmonic based photodetector
摘要： Recent era has witnessed a wide interest of researchers for the development of nano scale high speed photodetectors. Now days, optical communication systems demand these detectors with light enhancement along with high gain and bandwidth. Plasmonics based photodetectors with gold nanogratings are employed in literature for high responsivity and miniaturization. However, these devices need to be explored for other metals as gold being very costly. In this work, plasmonic based photodetector is designed with silver nanogratings and analyzed over varying shapes like rectangular, trapezoidal, ellipse and parabolic taper. Enhanced light absorption with quenching factor of 73.96% is achieved with rectangular grooves in near infrared region as compared to other shapes.
关键词： Surface plasmons (SPs),Absorption,Nano gratings,Enhancement,Plasmonic,Photo-detectors,Subwavelength aperture,Finite-difference,Time-domain (FDTD) simulation
更新于2025-09-12 10:27:22
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Negative terahertz conductivity and amplification of surface plasmons in graphene–black phosphorus injection laser heterostructures
摘要： We propose and evaluate the heterostructure based on the graphene layer (GL) with the lateral electron injection from the side contacts and the hole vertical injection via the black phosphorus layer (BL) (P+-PL-PL-GL heterostructure). Due to a relatively small energy of the holes injected from the PL into the GL (about 100 meV, smaller than the energy of optical phonons in the GL which is about 200 meV), the hole injection can effectively cool down the two-dimensional electron-hole plasma in the GL. This simpli?es the realization of the interband population inversion and the achievement of the negative dynamic conductivity in the terahertz (THz) frequency range enabling the ampli?cation of the surface plasmon modes. The latter can lead to the plasmon lasing. The conversion of the plasmons into the output radiation can be used for new types of the THz sources.
关键词： graphene,black phosphorus,terahertz,injection laser,surface plasmons
更新于2025-09-12 10:27:22
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Coupling of deterministically activated quantum emitters in hexagonal boron nitride to plasmonic surface lattice resonances
摘要： The cooperative phenomena stemming from the radiation field-mediated coupling between individual quantum emitters are presently attracting broad interest for applications related to on-chip photonic quantum memories and long-range entanglement. Common to these applications is the generation of electro-magnetic modes over macroscopic distances. Much research, however, is still needed before such systems can be deployed in the form of practical devices, starting with the investigation of alternate physical platforms. Quantum emitters in two-dimensional (2D) systems provide an intriguing route because these materials can be adapted to arbitrarily shaped substrates to form hybrid systems wherein emitters are near-field-coupled to suitable optical modes. Here, we report a scalable coupling method allowing color center ensembles in a van der Waals material (hexagonal boron nitride) to couple to a delocalized high-quality plasmonic surface lattice resonance. This type of architecture is promising for photonic applications, especially given the ability of the hexagonal boron nitride emitters to operate as single-photon sources at room temperature.
关键词： coupling,strain,delocalization,defect,quantum emission,photoluminescence,surface plasmons,hexagonal boron nitride,2D materials,surface lattice resonance
更新于2025-09-11 14:15:04