Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Spin-Selective Transmission and Devisable Chirality in Two-Layer Metasurfaces.

ABSTRACT: Chirality is a nearly ubiquitous natural phenomenon. Its minute presence in most naturally occurring materials makes it incredibly difficult to detect. Recent advances in metasurfaces indicate that they exhibit devisable chirality in novel forms; this finding offers an effective opening for studying chirality and its features in such nanostructures. These metasurfaces display vast possibilities for highly sensitive chirality discrimination in biological and chemical systems. Here, we show that two-layer metasurfaces based on twisted nanorods can generate giant spin-selective transmission and support engineered chirality in the near-infrared region. Two designed metasurfaces with opposite spin-selective transmission are proposed for treatment as enantiomers and can be used widely for spin selection and enhanced chiral sensing. Specifically, we demonstrate that the chirality in these proposed metasurfaces can be adjusted effectively by simply changing the orientation angle between the twisted nanorods. Our results offer simple and straightforward rules for chirality engineering in metasurfaces and suggest intriguing possibilities for the applications of such metasurfaces in spin optics and chiral sensing.

SUBMITTER: Li Z

PROVIDER: S-EPMC5557978 | biostudies-other | 2017 Aug

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Shared Molecules

Only show the datasets with similarity scores above: 0.5

Threshold

0.5

Similar Datasets

Coupling-enabled chirality in terahertz metasurfaces.

Project description:Chirality prevails in nature and is of great value for molecular biology, medicine, and bioscience. Due to the enhancement of chiroptical responses, chiral metasurfaces has attracted enormous attentions. In this paper, some novel polarization-sensitive transmission effects in terahertz chiral metasurfaces are exhibited. In the chiral metasurfaces whose unit cell consists of two basic resonators - a wire and a split ring resonator (SRR), we observe the asymmetrical transmission for circularly polarized state from the circular cross-polarization conversion spectra and the circular conversion dichroism (CCD). More importantly, we verify that the chiroptical activities can be affected by the coupling between the two resonators by simply moving their relative position in the terahertz metasurfaces. From the experimental and simulated results, we observe the distinguished variation in the circular cross-polarization conversion spectra and CCD, and combining with the theoretical analysis using coupled mode theory, we reveal that the chirality of the metasurfaces is strongly correlated to the coupling between the two modes determined by the wire and SRR. Finally, we demonstrate the coupling-enabled chirality by investigating the dependence of CCD on the coupling discrepancy with different relative positions of the two resonators. These findings offer the insights into the relationship between chirality and mode coupling and provide a theoretical method to design chiral metasurfaces and enhance the circular conversion dichroism, which have potential applications in the fields such as optical sensing, polarization imaging, and biological/chemical detection.

| S-EPMC11636346 | biostudies-literature

Perovskite metasurfaces with large superstructural chirality.

Project description:Recent attempts to synthesize hybrid perovskites with large chirality have been hampered by large size mismatch and weak interaction between their structure and the wavelength of light. Here we adopt a planar nanostructure design to overcome these limitations and realize all-dielectric perovskite metasurfaces with giant superstructural chirality. We identify a direct spectral correspondence between the near- and the far- field chirality, and tune the electric and magnetic multipole moments of the resonant chiral metamolecules to obtain large anisotropy factor of 0.49 and circular dichroism of 6350 mdeg. Simulations show that larger area metasurfaces could yield even higher optical activity, approaching the theoretical limits. Our results clearly demonstrate the advantages of nanostructrure engineering for the implementation of perovskite chiral photonic, optoelectronic, and spintronic devices.

| S-EPMC8943210 | biostudies-literature

Strong, spectrally-tunable chirality in diffractive metasurfaces.

Project description:Metamaterials and metasurfaces provide a paradigm-changing approach for manipulating light. Their potential has been evinced by recent demonstrations of chiral responses much greater than those of natural materials. Here, we demonstrate theoretically and experimentally that the extrinsic chiral response of a metasurface can be dramatically enhanced by near-field diffraction effects. At the core of this phenomenon are lattice plasmon modes that respond selectively to the illumination's polarization handedness. The metasurface exhibits sharp features in its circular dichroism spectra, which are tunable over a broad bandwidth by changing the illumination angle over a few degrees. Using this property, we demonstrate an ultra-thin circular-polarization sensitive spectral filter with a linewidth of ~10 nm, which can be dynamically tuned over a spectral range of 200 nm. Chiral diffractive metasurfaces, such as the one proposed here, open exciting possibilities for ultra-thin photonic devices with tunable, spin-controlled functionality.

| S-EPMC4559672 | biostudies-other

Nonvolatile chirality switching in terahertz chalcogenide metasurfaces.

Project description:Actively controlling the polarization states of terahertz (THz) waves is essential for polarization-sensitive spectroscopy, which has various applications in anisotropy imaging, noncontact Hall measurement, and vibrational circular dichroism. In the THz regime, the lack of a polarization modulator hinders the development of this spectroscopy. We theoretically and experimentally demonstrate that conjugated bilayer chiral metamaterials (CMMs) integrated with Ge2Sb2Te5 (GST225) active components can achieve nonvolatile and continuously tunable optical activity in the THz region. A THz time-domain spectroscopic system was used to characterize the device, showing a tunable ellipticity (from ‒36° to 0°) and rotation of the plane polarization (from 32° to 0°) at approximately 0.73 THz by varying the GST225 state from amorphous (AM) to crystalline (CR). Moreover, a continuously tunable chiroptical response was experimentally observed by partially crystallizing the GST225, which can create intermediate states, having regions of both AM and CR states. Note that the GST225 has an advantage of nonvolatility over the other active elements and does not require any energy to retain its structural state. Our work allows the development of THz metadevices capable of actively manipulating the polarization of THz waves and may find applications for dynamically tunable THz circular polarizers and polarization modulators for THz emissions.

| S-EPMC9525255 | biostudies-literature

Detection of a Chirality-Induced Spin Selective Quantum Capacitance in α-Helical Peptides.

Project description:Advanced Kelvin probe force microscopy simultaneously detects the quantum capacitance and surface potential of an α-helical peptide monolayer. These indicators shift when either the magnetic polarization or the enantiomer is toggled. A model based on a triangular quantum well in thermal and chemical equilibrium and electron-electron interactions allows for calculating the electrical potential profile from the measured data. The combination of the model and the measurements shows that no global charge transport is required to produce effects attributed to the chirality-induced spin selectivity effect. These experimental findings support the theoretical model of Fransson et al. Nano Letters 2021, 21 (7), 3026-3032. Measurements of the quantum capacitance represent a new way to test and refine theoretical models used to explain strong spin polarization due to chirality-induced spin selectivity.

| S-EPMC10510583 | biostudies-literature

Unusual Spin Polarization in the Chirality-Induced Spin Selectivity.

Project description:Chirality-induced spin selectivity (CISS) refers to the fact that electrons get spin polarized after passing through chiral molecules in a nanoscale transport device or in photoemission experiments. In CISS, chiral molecules are commonly believed to be a spin filter through which one favored spin transmits and the opposite spin gets reflected; that is, transmitted and reflected electrons exhibit opposite spin polarization. In this work, we point out that such a spin filter scenario contradicts the principle that equilibrium spin current must vanish. Instead, we find that both transmitted and reflected electrons present the same type of spin polarization, which is actually ubiquitous for a two-terminal device. More accurately, chiral molecules play the role of a spin polarizer rather than a spin filter. The direction of spin polarization is determined by the molecule chirality and the electron incident direction. And the magnitude of spin polarization relies on local spin-orbit coupling in the device. Our work brings a deeper understanding on CISS and interprets recent experiments, for example, the CISS-driven anomalous Hall effect.

| S-EPMC9706810 | biostudies-literature

Terahertz Spin-Conjugate Symmetry Breaking for Nonreciprocal Chirality and One-Way Transmission Based on Magneto-Optical Moire Metasurface.

Project description:In this work, the gyrotropic semiconductor InSb into the twisted bilayer metasurface to form a magneto-optical moiré metasurface is introduced. Through the theoretical analysis, the "moiré angle" is developed in which case the nonreciprocity and chirality with the spin-conjugate asymmetric transmission are obtained due to the simultaneous breaking of both time-reversal symmetry and spatial mirror symmetry. The experiments confirm that the chirality can be actively manipulated by rotating the twisted angle and the external magnetic field, realizing spin-conjugate asymmetric transmission. Meanwhile, the two spin states also realize the nonreciprocal one-way transmission, and their isolation spectra are also spin-conjugate asymmetric: one is enhanced up to 48 dB, and the other's bandwidth is widened to over 730 GHz. This spin-conjugate symmetry-breaking effect in the MOMM brings a combination of time-space asymmetric transmission, and it also provides a new scheme for the implementation of high-performance THz chirality controllers and isolators.

| S-EPMC9896033 | biostudies-literature

Nonclassical Spin-Multiplexing Metasurfaces Enabled Multifunctional Meta-Scope.

Project description:Dielectric metasurfaces have emerged as attractive devices for advanced imaging systems because of their high efficiency, ability of wavefront manipulation, and lightweight. The classical spin-multiplexing metasurfaces can only provide two orthogonal circular polarization channels and require high phase contrast which limits their applications. Here, metasurfaces with arbitrary three independent channels are demonstrated by proposing a nonclassical spin-multiplexing approach exploring the low refractive index meta-atoms. A zoom microscope with on-axis tri-foci and a synchronous achiral-chiral microscope with in-plane tri-foci based on silicon nitride metasurfaces are experimentally demonstrated. Based on the on-axis tri-foci metasurface, singlet zoom imaging with three magnifications and a broadband response (blue to red) based on a single metasurface is first demonstrated. A compact microscope (meta-scope) consisting of two metasurfaces with three magnifications of 9.5, 10, and 29X with diffraction-limited resolutions is further constructed, respectively. Utilizing the in-plane tri-foci metasurface, a singlet microscope with three achiral-chiral channels is demonstrated. It offers a magnification of 53X and a diffraction-limited resolution, enabling simultaneous imaging of an object's achiral and chiral properties. Our multifunctional metasurfaces and meta-scope approaches could boost the applications in biological imaging and machine vision.

| S-EPMC11618737 | biostudies-literature

Chirality transmission in macromolecular domains.

Project description:Chiral communications exist in secondary structures of foldamers and copolymers via a network of noncovalent interactions within effective intermolecular force (IMF) range. It is not known whether long-range chiral communication exists between macromolecular tertiary structures such as peptide coiled-coils beyond the IMF distance. Harnessing the high sensitivity of single-molecule force spectroscopy, we investigate the chiral interaction between covalently linked DNA duplexes and peptide coiled-coils by evaluating the binding of a diastereomeric pair of three DNA-peptide conjugates. We find that right-handed DNA triple helices well accommodate peptide triple coiled-coils of the same handedness, but not with the left-handed coiled-coil stereoisomers. This chiral communication is effective in a range (<4.5 nm) far beyond canonical IMF distance. Small-angle X-ray scattering and molecular dynamics simulation indicate that the interdomain linkers are tightly packed via hydrophobic interactions, which likely sustains the chirality transmission between DNA and peptide domains. Our findings establish that long-range chiral transmission occurs in tertiary macromolecular domains, explaining the presence of homochiral pairing of superhelices in proteins.

| S-EPMC8748818 | biostudies-literature

Unidirectional Chiral Emission via Twisted Bi-layer Metasurfaces.

Project description:Controlling and channeling light emissions from unpolarized quantum dots into specific directions with chiral polarization remains a key challenge in modern photonics. Stacked metasurface designs offer a potential compact solution for chirality and directionality engineering. However, experimental observations of directional chiral radiation from resonant metasurfaces with quantum emitters remain obscure. In this paper, we present experimental observations of unidirectional chiral emission from a twisted bi-layer metasurface via multi-dimensional control, including twist angle, interlayer distance, and lateral displacement between the top and bottom layers, as enabled by doublet alignment lithography (DAL). First, maintaining alignment, the metasurface demonstrates a resonant intrinsic optical chirality with near-unity circular dichroism of 0.94 and reflectance difference of 74%, where a high circular dichroism greater than 0.9 persists across a wide range of angles from -11 to 11 degrees. Second, engineered lateral displacement induces a unidirectional chiral resonance, resulting in unidirectional chiral emission from the quantum dots deposited onto the metasurface. Our bi-layer metasurfaces offer a universal compact platform for efficient radiation manipulation over a wide angular range, promising potential applications in miniaturized lasers, grating couplers, and chiral nanoantennas.

| S-EPMC11557933 | 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