Browse
Submit Data
Databases
API
Help

Dataset Information

20 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Controlling dispersion characteristics of terahertz metasurface.

ABSTRACT: Terahertz (THz) metasurfaces have been explored recently due to their properties such as low material loss and ease of fabrication compared to three-dimensional (3D) metamaterials. Although the dispersion properties of the reflection/transmission-type THz metasurface were observed in some published literature, the method to control them at will has been scarcely reported to the best of our knowledge. In this context, flexible dispersion control of the THz metasurface will lead to great opportunities toward unprecedented THz devices. As an example, a THz metasurface with controllable dispersion characteristics has been successfully demonstrated in this article, and the incident waves at different frequencies from a source in front of the metasurface can be projected into different desired anomalous angular positions. Furthermore, this work provides a potential approach to other kinds of novel THz devices that need controllable metasurface dispersion properties.

SUBMITTER: Qu SW

PROVIDER: S-EPMC4369731 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Controlling dispersion characteristics of terahertz metasurface.

Qu Shi-Wei SW Wu Wei-Wei WW Chen Bao-Jie BJ Yi Huan H Bai Xue X Ng Kung Bo KB Chan Chi Hou CH

Scientific reports 20150323

Terahertz (THz) metasurfaces have been explored recently due to their properties such as low material loss and ease of fabrication compared to three-dimensional (3D) metamaterials. Although the dispersion properties of the reflection/transmission-type THz metasurface were observed in some published literature, the method to control them at will has been scarcely reported to the best of our knowledge. In this context, flexible dispersion control of the THz metasurface will lead to great opportuni ...[more]

PMID: 25797336

Similar Datasets

Electrically addressable integrated intelligent terahertz metasurface.

Project description:Reconfigurable intelligent surfaces (RISs) play an essential role in various applications, such as next-generation communication, uncrewed vehicles, and vital sign recognizers. However, in the terahertz (THz) region, the development of RISs is limited because of lacking tunable phase shifters and low-cost sensors. Here, we developed an integrated self-adaptive metasurface (SAM) with THz wave detection and modulation capabilities based on the phase change material. By applying various coding sequences, the metasurface could deflect THz beams over an angle range of 42.8°. We established a software-defined sensing reaction system for intelligent THz wave manipulation. In the system, the SAM self-adaptively adjusted the THz beam deflection angle and stabilized the reflected power in response to the detected signal without human intervention, showing vast potential in eliminating coverage dead zones and other applications in THz communication. Our programmable controlled SAM creates a platform for intelligent electromagnetic information processing in the THz regime.

| S-EPMC9555782 | biostudies-literature

Flat Terahertz Reflective Focusing Metasurface with Scanning Ability.

Project description:The ability to manipulate the propagation properties of electromagnetic waves, e.g., divergence, focusing, holography or deflection, is very significant in terahertz applications. Metasurfaces with flat structures are attractive for achieving such manipulations in terahertz band, as they feature low profile, lightweight, and ease of design and installation. Several types of terahertz reflective or transmitting metasurfaces with focusing function have been implemented recently, but none of them can provide scanning ability with controllable focus. Here, a flat reflective metasurface featuring controllable focal shift is proposed and experimentally demonstrated. Furthermore, the principle of designing a focus scanning reflective metasurface is presented and the focusing characteristics are discussed, including focus scanning along a line parallel or orthogonal to the metasurface with a large bandwidth. These interesting properties indicate that this flat reflective metasurface could play a key role in many terahertz imaging and detection systems.

| S-EPMC5471233 | biostudies-literature

Optically tunable terahertz chiral metasurface based on multi-layered graphene.

Project description:Active manipulation of the polarization states at terahertz frequencies is crucially helpful for polarization-sensitive spectroscopy, having significant applications such as non-contact Hall measurements, vibrational circular dichroism measurements and anisotropy imaging. The weakness of polarization manipulation provided by natural materials can be overcomed by chiral metamaterials. Chiral metamaterials have a huge potential to achieve the necessary polarization effects, hence they provide the basis for applications such as ultracompact polarization components. Terahertz chiral metamaterials that allow dynamic polarization modulation of terahertz waves are of great practical interest and still challenging. Here, we show that terahertz metasurface based on the four conjugated "petal" resonators integrated with multi-layered graphene (MLG) can enable dynamically tunable chiroptical response using optical pumping. In particular, a change of ellipticity angle of 20° is observed around 0.76 THz under optical pumping by a 980 nm continuous wave (CW) laser. Furthermore, using temporal coupled-mode theory, our study also reveals that the chiroptical response of the proposed multi-layered graphene-based metasurface is strongly dependent on the influence of optical pumping on the loss parameters of resonance modes, leading to actively controllable polarization states of the transmitted terahertz waves. The present work paves the way for the realization of fundamental terahertz components capable for active polarization manipulation.

| S-EPMC7035278 | biostudies-literature

Broadband diffuse terahertz wave scattering by flexible metasurface with randomized phase distribution.

Project description:Suppressing specular electromagnetic wave reflection or backward radar cross section is important and of broad interests in practical electromagnetic engineering. Here, we present a scheme to achieve broadband backward scattering reduction through diffuse terahertz wave reflection by a flexible metasurface. The diffuse scattering of terahertz wave is caused by the randomized reflection phase distribution on the metasurface, which consists of meta-particles of differently sized metallic patches arranged on top of a grounded polyimide substrate simply through a certain computer generated pseudorandom sequence. Both numerical simulations and experimental results demonstrate the ultralow specular reflection over a broad frequency band and wide angle of incidence due to the re-distribution of the incident energy into various directions. The diffuse scattering property is also polarization insensitive and can be well preserved when the flexible metasurface is conformably wrapped on a curved reflective object. The proposed design opens up a new route for specular reflection suppression, and may be applicable in stealth and other technology in the terahertz spectrum.

| S-EPMC4881048 | biostudies-literature

A Polarization-Insensitive and Wide-Angle Terahertz Absorber with Ring-Porous Patterned Graphene Metasurface.

Project description:A broadband terahertz (THz) absorber, based on a graphene metasurface, which consists of a layer of ring-porous patterned structure array and a metallic mirror separated by an ultrathin SiO2 dielectric layer, is proposed and studied by numerical simulation. The simulated results show that the absorptivity of the absorber reaches 90% in the range of 0.91-1.86 THz, and the normalized bandwidth of the absorptivity is 68.6% under normal incidence. In the simulation, the effects of the geometric parameters of the structure on the absorption band have been investigated. The results show that the absorber is insensitive to the incident polarization angle for both transverse electric (TE) and transverse magnetic (TM) under normal incidence. In addition, the absorber is not sensitive to oblique incidence of the light source under TE polarization conditions, and has an approximately stable absorption bandwidth at the incident angle from 0° to 50°. The absorption band can be adjusted by changing the bias voltage of the graphene Fermi level without varying the nanostructure. Furthermore, we propose that a two-layer graphene structure with the same geometric parameters is separated by a dielectric layer of appropriate thickness. The simulated results show that the absorptivity of the two-layer absorber reaches 90% in the range of 0.83-2.04 THz and the normalized bandwidth of the absorptivity is 84.3% under normal incidence. Because of its excellent characteristics based on graphene metamaterial absorbers, it has an important application value in the field of subwavelength photonic devices.

| S-EPMC7407757 | biostudies-literature

Convolution Operations on Coding Metasurface to Reach Flexible and Continuous Controls of Terahertz Beams.

Project description:The concept of coding metasurface makes a link between physically metamaterial particles and digital codes, and hence it is possible to perform digital signal processing on the coding metasurface to realize unusual physical phenomena. Here, this study presents to perform Fourier operations on coding metasurfaces and proposes a principle called as scattering-pattern shift using the convolution theorem, which allows steering of the scattering pattern to an arbitrarily predesigned direction. Owing to the constant reflection amplitude of coding particles, the required coding pattern can be simply achieved by the modulus of two coding matrices. This study demonstrates that the scattering patterns that are directly calculated from the coding pattern using the Fourier transform have excellent agreements to the numerical simulations based on realistic coding structures, providing an efficient method in optimizing coding patterns to achieve predesigned scattering beams. The most important advantage of this approach over the previous schemes in producing anomalous single-beam scattering is its flexible and continuous controls to arbitrary directions. This work opens a new route to study metamaterial from a fully digital perspective, predicting the possibility of combining conventional theorems in digital signal processing with the coding metasurface to realize more powerful manipulations of electromagnetic waves.

| S-EPMC5096125 | biostudies-literature

Controlling frequency dispersion in electromagnetic invisibility cloaks.

Project description:Electromagnetic cloaking, as challenging as it may be to the physicist and the engineer has become a topical subject over the past decade. Thanks to the transformations optics (TO) invisibility devices are in sight even though quite drastic limitations remain yet to be lifted. The extreme material properties which are deduced from TO can be achieved in practice using dispersive metamaterials. However, the bandwidth over which a metamaterial cloak is efficient is drastically limited. We design and simulate a spherical cloak which takes into account the dispersive nature of relative permittivity and permeability tensors realized by plasma-like metamaterials. This spherical cloak works over a broad frequency-band even though these materials are of a highly dispersive nature. We establish two equations of state that link the eigenvalues of the permittivity and permeability tensors in every spherical cloak regardless of the geometrical transformation. Frequency dispersive properties do not disrupt cloaking as long as the equations of states are satisfied in the metamaterial cloak.

| S-EPMC6465290 | biostudies-literature

Terahertz polarization sensing based on metasurface microsensor display anti-proliferation of tumor cells with aspirin.

Project description:The inhibition effects of aspirin on cell proliferation are investigated by both traditional THz resonance sensing and the improved THz polarization sensing method based on a polarization dependent metasurface microsensor. Compared to resonance sensing, the quality factor of polarization sensing is 4?5 times higher than that of resonance sensing, and its figure of merit is at least one order of magnitude higher than that of the resonance sensing with the same metasurface microsensor. Our proposed metasurface-based biosensors may supply a novel viewpoint on cell proliferation from a physical perspective and be a valuable complementary reference for biological study.

| S-EPMC7249843 | biostudies-literature

Switchable Ultrathin Quarter-wave Plate in Terahertz Using Active Phase-change Metasurface.

Project description:Metamaterials open up various exotic means to control electromagnetic waves and among them polarization manipulations with metamaterials have attracted intense attention. As of today, static responses of resonators in metamaterials lead to a narrow-band and single-function operation. Extension of the working frequency relies on multilayer metamaterials or different unit cells, which hinder the development of ultra-compact optical systems. In this work, we demonstrate a switchable ultrathin terahertz quarter-wave plate by hybridizing a phase change material, vanadium dioxide (VO2), with a metasurface. Before the phase transition, VO2 behaves as a semiconductor and the metasurface operates as a quarter-wave plate at 0.468 THz. After the transition to metal phase, the quarter-wave plate operates at 0.502 THz. At the corresponding operating frequencies, the metasurface converts a linearly polarized light into a circularly polarized light. This work reveals the feasibility to realize tunable/active and extremely low-profile polarization manipulation devices in the terahertz regime through the incorporation of such phase-change metasurfaces, enabling novel applications of ultrathin terahertz meta-devices.

| S-EPMC4595731 | biostudies-other

Electro-mechanical light modulator based on controlling the interaction of light with a metasurface.

Project description:We demonstrate a reflective light modulator, a dynamic Salisbury screen where modulation of light is achieved by moving a thin metamaterial absorber to control its interaction with the standing wave formed by the incident wave and its reflection on a mirror. Electrostatic actuation of the plasmonic metamaterial absorber's position leads to a dynamic change of the Salisbury screen's spectral response and 50% modulation of the reflected light intensity in the near infrared part of the spectrum. The proposed approach can also be used with other metasurfaces to control the changes they impose on the polarization, intensity, phase, spectrum and directional distribution of reflected light.

| S-EPMC5511214 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data