A simple design of a tunable ultra-broadband metamaterial absorber terahertz (THz) radiation based on vanadium dioxide (VO 2 ) configurations is proposed, having wide incidence angle tolerance and polarization insensitivity.

Localized surface plasmon resonance in capacitively-coupled metallic-core dielectric-shell nanoparticle dimers is accompanied by a substantial local field enhancement the interparticle gap area enabling low-threshold optical bistability.

Abstract We investigated the resonant interaction of incident microwaves with a finite linear array equidistantly arranged conductive rods height. When strong coupling is established between adjacent rods, which act as open resonators for radial waves, series resonances emerges, corresponding to number in array. Each resonance exhibits distinct charge oscillation amplitudes and phases along leading varying radiative losses. Notably, system two resonantly interacting antiphase oscillations...

Film-coupled plasmonic resonators offer efficient platforms for light enhancement due to the excitation of gap surface plasmons (GSPs) at metal-insulator-metal interfaces, where electromagnetic energy is stored within spacer. In applications like biosensing and spontaneous emission control, spatial overlap between target molecule hotspots essential. Here, we propose utilizing controllable, capabilities a specifically designed GSP disk resonator enhancement. To create an external hotspot make...

The resonant interaction of a dielectric-coated conductive rod with the X-band microwave field is investigated. magnetic distribution Goubau standing radial surface waves was experimentally visualized by using thermo-elastic optical indicator microscope, and corresponding electric determined via numerical simulations. These distributions are characterized certain pattern antinodes distinctive for waves. An analysis these allows one to couple coated cut line. A placed in gap region...

Nowadays, Au dimer-based nanostructures are exhaustively studied due to their outstanding potential as plasmonic nanoantennas for future applications in high-sensitivity molecular sensing by Surface-Enhanced Raman Spectroscopy (SERS). In this work, we analyze nano-gapped nanowires (NWs) or Au-NWs dimers designing efficient nanoantennas, reporting an exhaustive study about dimer length and laser polarization orientation effects on SERS-based performance. Arrays of with gaps 22 (+/-)4 [nm],...

Abstract The resonant response of a thin conducting rod with finite length irradiated by microwaves polarized along its axis is observed. By using thermoelastic optical indicator microscope it shown that several half- wavelengths can serve as resonator for axial surface waves. It facilitated noticeable reflections (approximately 30%) from the edges conditioned unique distributions Sommerfeld wave fields rod. presence weak electric field component waves ensures an easy coupling incident plane...

Abstract The operation of the metasurface based on silicon cylindrical rings coated by a gold as terahertz (THz) bandpass filter/antireflection structure is studied. decrease in reflectance conditioned destructive interference electromagnetic waves reflected from structural layers metasurface. An efficient antireflection band with below 10% formed frequency spectrum 0.71–0.92 THz relative bandwidth 26%. It shown that operating suggested can be varied changing total radius rings, whereas...

We suggest to exploit dielectric-metal core-shell nanostructures for efficient resonant and yet broadband absorption of infrared radiation with deeply subwavelength configurations. Realizing that would efficiently absorb only when their dielectric properties match those the environment making use effective medium approach, we develop design strategy using very thin shells made poor metals, i.e., metals having real imaginary parts permittivities same order magnitude. Analyzing in detail...

Glucose concentration in the aqueous solution was measured using a microwave metamaterial sensor based on modified Hilbert curve of first fractal order. In order to increase system sensitivity at fixed meta-element sizes, design optimized by finite element method. It observed that $ S parameters microstrip line resonant frequencies strongly depend glucose concentration. Consequently, measuring responses for different concentrations one can detect solution. Such structure be useful biological...

We propose a thin, compact, broadband, polarization and angle insensitive metamaterial absorber based on tungsten reflector, silicon spacer, top pattern composed of double square-like ring resonator utilizing nickel (Ni). In such structure, high absorption (above 80%) bandwidth ∼4.8µm from 3.52 up to 8.32 µm corresponding the relative ∼81% can be achieved with deeply subwavelength unit cell dimensions. Here physical origin broadband is associated low Q-factor dipole modes inner outer sides...

Abstract Visualizations of the microwave electric and magnetic near-field distributions radio-frequency (RF) filters were performed using technique thermoelastic optical indicator microscopy (TEOIM). New indicators based on periodic dielectric-metal structures designed for field visualization. Depending structure orientation, such metasurface-based allow separately visualization E x y components in-plane field. Numerical simulations conducted to examine working principle structures, results...

Abstract We experimentally demonstrate that the transmission of microwave electromagnetic fields through a bilayer metasurface (BMS) composed thin conductive rods can abruptly change in narrow frequency range. A theoretical analysis based on coupled oscillator model is performed to reveal physical mechanism behind frequency-dependent properties such structure. Two conditions primarily facilitate observed high dispersion BMS. The first one resonant interaction between incident microwaves and...

The optical bistability caused by the coupling between modes of parallel-plate waveguide and a nonlinear hemicylindrical crystal is studied using theoretical numerical analysis. In such system channel parallelly coupled to whispering gallery microresonator ensuring bistable behaviour at input intensities order few MW/cm2. characteristic minimum switching time (around 30 ps) can be controlled varying thickness metal layer which couples modes. This conditioned change quality Q-factor, as well...

The semicylindrical microresonator with relatively simple excitation a plane wave is studied. resonator formed on the base of dielectric/metal/dielectric structure, where energy penetrates into through thin metal layer and stored in dielectric high permittivity. proposed combines features Fabry-Perot Whispering gallery mode resonators. Dependence radiation losses radius materials are estimated by theoretical analysis, while shown via numerical analysis. quality Q-factor can achieve up to...

Abstract Scanning near-field optical microscopy (SNOM) is a well-known powerful technique for visualization of surface nanostructures and fields far beyond the diffraction limit thus indispensable in material- nanoscience. While SNOM resolution theoretically unlimited, performance practice constrained by signal-to-background ratio, simply because light scattering scaling down as sixth power nanoparticle size useful signals rapidly drowning background very small objects. In modern...

The resonant interaction of a dielectric-coated conductive rod with the X-band microwave field is investigated. magnetic distribution Goubau standing radial surface waves was experimentally visualized by using thermo-elastic optical indicator microscope, and corresponding electric determined via numerical simulations. These distributions are characterized certain pattern antinodes distinctive for waves. An analysis these allows one to couple coated cut line. A placed in gap region...