High-Performance Tunable Plasmonic Absorber Based on the Metal-Insulator-Metal Grating Nanostructure

Plasmonics - A new high-performance plasmonic absorber based on the metal-insulator-metal grating nanostructure is proposed and numerically studied. The effect of geometric parameters of grating...     

Tunable Terahertz Plasmonic Perfect Absorber Based on T-Shaped InSb Array

High absorption efficiency is particularly desirable for various microtechnological applications. In this paper, a nearly perfect terahertz absorber for transverse magnetic (TM) polarization based on T-shaped InSb array is proposed and numerically investigated. Incident wave at the Fabry-Perot resonant frequency can be totally absorbed into the narrow grooves between the two adjacent T-shaped InSb arms. The absorption mechanism is theoretically and numerically studied by using the Fabry-Perot model and the finite element method (FEM), respectively. It is found that the proposed absorber has large angle tolerance. Moreover, the absorption peak can be controlled by varying the temperature. Furthermore, a new absorption peak will emerge while breaking the symmetry of the T-shaped InSb array. This tunable and angle-independent THz perfect absorber may find important applications in THz devices such as microbolometers, coherent thermal emitters, solar cells, photo detectors, and sensors.     

Tunable Plasmonic Absorber Based on Propagating and Localized Surface Plasmons Using Metal-Dielectric-Metal Structure

We propose a metal-dielectric-metal super absorber based on propagating and localized surface plasmons which exhibits a near perfect absorption in the visible and near-infrared spectrum. The absorber consists of Ag/Al₂O₃/Al triple layers in which the top Al layer is a periodic nano disk array. The absorption spectrum can be easily controlled by adjusting the structure parameters including the period and radius of the nano disk and the maximal absorption can reach 99.62 %. We completely analyze the PSPs and LSPs modes supported by the MDM structure and their relationship with the ultrahigh absorption. Moreover, we propose a novel idea to further enhance the absorption by exciting the PSPs and high-order LSPs modes simultaneously, which is different from the previous works. This kind of absorber using stable inexpensive Al instead of noble metal Au or Ag is an appropriate candidate for photovoltaics, spectroscopy, photodetectors, sensing, and surface-enhanced Raman spectroscopy (SERS).     

Plasmonic Near-Field Effect on Visible and Near-Infrared Emissions from Self-Assembled Gold Nanoparticle Films

Plasmonics - In this work, we have performed a systematic investigation of the plasmon near-field effect on photoluminescence (PL) behavior of the annealed self-assembled gold nanostructured films....     

Gold Nanowires-Based Hyperbolic Metamaterial Multiband Absorber Operating in the Visible and Near-Infrared Regimes

Plasmonics - Spectral feature of gold nanowires-based hyperbolic metamaterial (NWHMM) absorber was investigated. The absorber has NWHMM surface as the top layer, which is composed of periodically...     

Design Method of a Broadband Wide-Angle Plasmonic Absorber in the Visible Range

A new design method of a broadband wide-angle metal-dielectric-metal plasmonic absorber is presented based on the cavity mode theory. The broadband absorption is implemented by filling a unit cell with multi-size square metal patches resonant at adjacent wavelengths, with the widths of the patches and thickness of the dielectric layer optimized with the presented method. A broadband plasmonic absorber working in the visible range is designed, the absorption of which is insensitive to the azimuth angle of incident field and keeps over 0.7 at incident angle up to 60° for p polarization and above 0.6 at up to 40° for s polarization.     

Tunable Omnidirectional Broadband Band-Stop Filter in Symmetric Hybrid Plasmonic Structures

We numerically investigate a symmetric hybrid waveguide-plasmon system composed of a periodic metallic nanowires pairs array embedded in symmetric dielectric sandwich layers for band-stop filtering in the optical frequency range. The proposed symmetric system shows an omnidirectional broadband absorption enhancement with flat band-stop transmission induced by the coupling and hybridization of photonic and plasmonic modes. The transmission stop band bandwidth ranging from 80 to 585 nm is observed. The bandwidth of the proposed system can be further manipulated by tailoring their geometrics for potential applications in plasmonic-assisted broadband optical filtering.     

High-quality Temperature Sensor Based on the Plasmonic Resonant Absorber

Plasmonics - Aiming at the achievement of temperature measurement with high sensitivity in the sub-wavelength scale, an all-metal meta-surface (AMMS)-based sensor is numerically demonstrated. Based...     

Multiband Terahertz Metamaterial Absorber Based on Multipolar Plasmonic Resonances

Terahertz metamaterial absorbers (MMA) have found wide scope of research prospective, remarkably in the development of multiband absorbers. Considerable applications are established using these multiband absorbers in THz imaging, wireless communication and bolometric detectors. The MMA was built on a GaAs substrate of 30 µm thickness and the hexagonal metallic pattern was etched out on a gold layer of 0.4 µm thickness on the top surface. The underlying ground layer is metallic backed. This design realizes the multiband (9-bands) of absorption in the spectral region from 0.56 to 0.92 THz. The multiband absorption mechanism of the absorber was examined by electric field dispersion analysis and impedance matching concept. From the established results, the absorber exhibits nine bands within a narrow frequency range and secures promising applications in hyperspectral imaging, clinical sensing and detection.

     

An Ultra-broadband Single Polarization Filter Based on Plasmonic Photonic Crystal Fiber with a Liquid Crystal Core

Plasmonics - An ultra-broadband single polarization filter based on plasmonic photonic crystal fiber with a liquid crystal core is investigated using the full-vectorial finite element method....     

Design and Analysis of Infrared Tunable All-Optical Filters Based on Plasmonic Hybrid Nanostructure Using Periodic Nanohole Arrays

A tunable high transmission optical bandpass filter based on a plasmonic hybrid nanostructure, composed of a periodic array of nanocircles and nanoholes combining two isolated waveguides is introduced in this paper. The presented design improves the coupling, which results in a higher transmission peak. To study the filtering operation, different topologies are investigated. The transmission properties and the resonance wavelengths are adjusted by sweeping various geometrical parameters. A multimode spectrum for each of the topologies is obtained. A tunable bandgap and bandwidth can be obtained by adjusting the refractive index of the periodic nanostructure. We have reached a maximum quality factor and a small full width at half-maximum bandwidth with the maximum transmission values greater than 80%. The advantages of the presented structures which include the benefits of both plasmonic and periodic nanostructures are tunability, high detection resolution, and integrability at the nanoscale for optical applications.

     

Tunable Terahertz Filters Based on Graphene Plasmonic All-Dielectric Metasurfaces

A tunable terahertz filter based on graphene plasmonic all-dielectric metasurfaces is proposed and investigated numerically by using the finite-difference time-domain (FDTD) method. Especially, hybrid all-dielectric metasurfaces are used to make a whole single-sheet graphene forms two different conductivity patterns with the same gate voltage. The simulated results show that resonance wavelength is shifted significantly with the change of gate voltage. Besides, the transmittance spectra are also shifted with the change of the width of SiC, and the filter shows a polarization-dependent modulation property for the length and the width of SiC being 480 and 320 nm, respectively. In addition, the filter can be applied for refractive sensing because the transmittance spectra are shifted with the change of the background refractive index. The study could provide availability for versatile tunable terahertz graphene plasmonic metasurfaces.     

Enhanced Optical Transmission Assisted Near-Infrared Plasmonic Optical Filter via Hybrid Subwavelength Structures

Plasmonics - Enhanced optical transmission (EOT), which results from the incident light interacting with the subwavelength nanostructures patterned in a metallic film, showcases the excitation of...     

A Hybrid Plasmonic Modulator Based on Graphene on Channel Plasmonic Polariton Waveguide

A hybrid plasmonic modulator based on graphene on channel plasmonic polariton waveguide was proposed to overcome the difficulty in achieving high-speed modulation on the nanometric plasmonic waveguide platform. The extinction ratio and the figure of merit of the proposed modulator were analyzed in detail, and a tradeoff between them was found due to the intrinsic loss of the channel plasmonic polariton waveguide. And an optimized hybrid plasmonic modulator with large modulation bandwidth of 0.662 THz, low power consumption of 118.7 fJ/bit, and short device length of 7.680 μm was obtained theoretically. In addition, the proposed hybrid plasmonic modulator based on graphene on channel plasmonic polariton waveguide is easy to fabricate and provides a potential solution for the high-speed plasmonic modulator.

     

Tunable Multimode Plasmonic Filter Based on Side-Coupled Ring-Groove Joint Resonator

Plasmonics - A tunable multimode plasmonic filter is proposed by using a side-coupled ring-groove joint resonator. In addition to the integer resonance modes of the perfect ring resonator (RR),...     

Plasmonic Variable Optical Attenuator Based on Liquid-Crystal Tunable Stripe Waveguides

A long-range surface plasmon polariton variable optical attenuator based on available nematic liquid crystals and polymers is proposed and theoretically investigated. It is demonstrated that the electro-optic control of the nematic molecular orientation is capable of tuning the level of index asymmetry of an Au stripe waveguide and the key properties of the fundamental long-range plasmonic mode, such as modal profile and propagation losses. By proper structural design and material selection, plasmonic in-line intensity modulators are designed, which exhibit very low power consumption, extinction ratios in excess of 30 dB, and insertion losses as low as 1 dB for a device length in the millimeter range. Such active plasmonic elements are envisaged to be used in interchip photonics bus interconnects.     

Polarization-Independent Near-Perfect Absorber in the Visible Regime Based on One-Dimensional Meta-Surface

Plasmonics - We present a polarization-independent near-perfect absorber in the visible regime based on one-dimensional meta-surface. In this absorber, the dielectric grating layer with high...     

Novel Multi-Broadband Plasmonic Absorber Based on a Metal-Dielectric-Metal Square Ring Array

Plasmonics - We numerically analyzed a simple and novel design of multi-broadband plasmonic absorber which consists of a planar array of thin gold square ring structures on dielectric/metal...     

Applications of Tunable Mid-Infrared Plasmonic Square-Nanoring Resonator Based on Graphene Nanoribbon

Plasmonics - In this work, different structures are designed based on graphene square-nanoring resonator (GSNR) and simulated by the three-dimensional finite-difference time-domain (3D-FDTD)...