An active absorption device is proposed based on vanadium dioxide metamaterials. By controlling the conductivity of dioxide, resonant absorbers are designed to work at wide range terahertz frequencies. Numerical results show that a broadband absorber with nearly 100% absorptance can be achieved, and its normalized bandwidth 90% 60% under normal incidence for both transverse-electric transverse-magnetic polarizations when equal 2000 Ω-1cm-1. Absorptance peak frequencies continuously tuned...

We present the bifunctional design of a broadband absorber and polarization converter based on switchable metasurface through insulator-to-metal phase transition vanadium dioxide. When dioxide is metal, designed behaves as absorber. This composed square, silica spacer, film. Calculated results show that in frequency range 0.52-1.2 THz, system can absorb more than 90% energy, bandwidth ratio 79%. It insensitive to due symmetry, still work well even at large incident angles. an insulator,...

We demonstrate that a broadband terahertz absorber with near-unity absorption can be realized using net-shaped periodically sinusoidally-patterned graphene sheet, placed on dielectric spacer supported metallic reflecting plate. Because of the gradient width modulation unit continuous plasmon resonances excited, and therefore achieved. The results show absorber's normalized bandwidth 90% absorbance is over 65% under normal incidence for both TE TM polarizations when chemical potential set as...

Based on the phase-transition property of vanadium dioxide (VO 2 ), a terahertz bifunctional absorber is proposed with switchable functionalities broadband absorption and multiband absorption. When VO metal, system regarded as absorber, which composed patch, topas spacer, film metallic disks inserted. The obtains absorptance >90% from 3.25 THz to 7.08 THz. Moreover, designed has stable performance within incident angle range 50°. dielectric, six peaks realized in system. Graphene...

A bifunctional metamaterial is proposed based on a hybrid graphene and vanadium dioxide (VO 2 ) configuration, which can realize dynamic switch between beam steering broadband absorption. The structure consists of VO square, patch, topas spacer, film, metal substrate. When in the metallic state, serves as coding metamaterial. By engineering different sizes top square adjusting Fermi energy level graphene, incident wave scattered patterns. dielectric absorber. changing from 0.0 eV to 0.9 eV,...

Polarization is an important characteristic of electromagnetic wave. Due to novel optical properties, graphene-based anisotropic structure widely used control polarization state In this work, four meta-atoms are designed regulate terahertz wave by changing Fermi energy level graphene. When 0.01 eV, cross-polarized emitted with phase difference 90° at 1.18 THz, and the corresponding conversion ratio reaches ∼90%. adjusted 0.70 linear gradient will disappear, almost disappears. Using selected...

In recent years, metasurfaces have attracted considerable interest for their unprecedented capabilities to manipulate intensity, phase, and polarization of an electromagnetic wave. Although metasurface-based wavefront modulation has achieved numerous successful results, implementation multifunctional devices in a single metasurface still meet significant challenges. Here, novel multilayer structure is designed using properties vanadium dioxide (VO

A multilayer metamaterial with switchable functionalities is presented based on the phase-transition property of vanadium dioxide. When dioxide in metallic state, a broadband absorber formed. Calculated results show that combination two absorption peaks enables absorptance more than 90% wide spectral range from 0.393 THz to 0.897 THz. Absorption performance insensitive polarization at small incident angle and work well even larger angle. insulating designed system behaves as narrowband...

We present a tunable metamodulator to work at terahertz frequencies by employing the dependency of toroidal dipolar resonance on conductivity vanadium dioxide. Numerical results show that in proposed planar structure can be observed around 0.288 THz transmission spectrum. From distribution anti-phase current flowing symmetric split ring resonator, formation dipole is validated. Our design may have potential applications advanced devices, such as filter, plasmonic sensor, and fast switch.

A terahertz bifunctional absorber is presented with broadband and narrowband absorbing properties in a graphene-spacer-vanadium dioxide-spacer-metal configuration. Carrier relaxation time of graphene τ = 1.0ps (τ 0.1ps) chosen for (broadband) absorption. When vanadium dioxide the conducting state, design behaves as absorber, it composed square-shaped graphene, topas spacer, metallic film. There an absorption band 100% absorptance at frequency 1.37 THz. Narrowband caused by localized magnetic...

By introducing vanadium dioxide film into a multilayer structure, the dual functionalities of perfect absorption and high transmission are presented using insulator-to-metal phase transition dioxide. When is in conducting state, designed system acts as narrowband absorber. The proposed absorber composed top metallic ring, silica spacer, film. peak originated from localized magnetic resonance between ring insulating transparent metal. middle dielectric subwavelength mesh combined together to...

An ultra-broadband absorber is introduced based on a multilayer graphene structure. Wave absorption of the optimized device >90% in bandwidth between 1.12 THz and 3.78 THz. Electric field distributions are studied to analyze working mechanism. Because symmetrical structure, designed not sensitive polarization state incident wave under small angles. The has reasonable tolerance for intensity modulated with wide range tunability by different Fermi energy levels graphene. This kind...

We present an isotropic active analog of electromagnetically induced transparency through conductivity tuning vanadium dioxide at terahertz frequencies. The unit cell the designed metasurface consists metallic split ring resonators and a cross, which have identical resonance frequencies for excitable lowest order modes but very different linewidths. By integrating into bottom metasurface, obvious window occurs under conductivities. Calculated results show that resonant transmission frequency...

The design of a broadband tunable absorber is proposed based on thin vanadium dioxide metasurface, which composed simple array and bottom gold film. When the conductivity equal to 2000 Ω <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> cm , simulated absorptance exceeds 90% with 71% bandwidth from 0.47 0.99 THz full width at half maximum 98% 0.354 1.036 center frequency 0.695 THz. Simulated results show that peak can be tuned 5% 100%...

A switchable metamaterial with bifunctionality of absorption and electromagnetically induced transparency is proposed based on the phase-transition characteristic phase change material-vanadium dioxide. When vanadium dioxide in metallic state, an isotropic narrow absorber obtained terahertz region, which consists a top cross, middle dielectric layer, bottom film. By adjusting structure parameters, perfect realized at frequency 0.498 THz. This designed insensitive to polarization incident...

Due to the physically unrestricted set of orthogonally helical modes orbital angular momentum (OAM), it has contributed significantly wireless communication and information capacity. Meanwhile, focusing important applications in fields such as super-resolution microscopic imaging optical integration. Plasmonic metasurfaces have a powerful ability modulate electromagnetic (EM) waves, diversified functionalities them are strongly desired. As today, few plasmonic reported which multi-function...

Thanks to switchable wavefronts, design methods of diverse functions are greatly enriched. However, less attention has been paid multichannel orbital angular momentums (OAMs) metasurfaces in previous reports. In this work, a spin-selective metasurface enabling OAMs is proposed terahertz band. This designed based on the phase change property vanadium dioxide (VO2). Firstly, when VO2 metal, vortex beam with topological charge l = 2 achieved under left-handed circular polarization (LCP)...