Topic
Circular polarization
About: Circular polarization is a research topic. Over the lifetime, 15201 publications have been published within this topic receiving 234418 citations.
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TL;DR: It is demonstrated that rotationally symmetric chiral metasurfaces can support sharp resonances with the maximum optical chirality determined by precise shaping of bound states in the continuum (BICs), and a realization of such chiral BIC metAsurfaces based on pairs of dielectric bars is proposed.
Abstract: We demonstrate that rotationally symmetric chiral metasurfaces can support sharp resonances with the maximum optical chirality determined by precise shaping of bound states in the continuum (BICs) Being uncoupled from one circular polarization of light and resonantly coupled to its counterpart, a metasurface hosting the chiral BIC resonance exhibits a narrow peak in the circular dichroism spectrum with the quality factor limited by weak dissipation losses We propose a realization of such chiral BIC metasurfaces based on pairs of dielectric bars and validate the concept of maximum chirality by numerical simulations
148 citations
TL;DR: In this article, the angular distribution of the photoelectrons created by photoionization of a given enantiomer, even when the target molecules are randomly oriented, was investigated for C3H6O3 structural isomers lactic acid and glyceraldehyde.
Abstract: The differing interaction of left and right circularly polarized light with chiral molecules is shown to lead to different angular distributions of the photoelectrons created by photoionization of a given enantiomer, even when the target molecules are randomly oriented Numerical calculations are presented to demonstrate the magnitude of this effect for the C3H6O3 structural isomers lactic acid and glyceraldehyde, including two different conformations of the latter Circular dichroism in the angular distributions (CDAD) of the valence electrons of these biomolecules is most pronounced close to threshold, but tends to vanish as the electron kinetic energy approaches 20 eV and above CDAD signals are predicted to range, typically, from 10% to 40% and sometimes to more than 60% of the differential cross section
148 citations
TL;DR: In this paper, a planar array of passive lens elements can be phased to approximate the effect of a curved dielectric lens, and two lenses have been designed to collimate radiation from a feed horn into a beam pointing 20° from broadside.
Abstract: A planar array of passive lens elements can be phased to approximate the effect of a curved dielectric lens. The rotational orientation of each element can provide the required phase shift for circular polarization. The array elements must be designed so that the hand of circular polarization changes as the electromagnetic wave passes through the lens. An element is presented that is based on an aperture-coupled microstrip patch antenna, and two lenses are designed. Each lens has a diameter of 254 mm and contains 349 elements. The elements have identical dimensions but the rotational orientation of each element is selected to provide a specific lens function. The first lens is designed to collimate radiation from a feed horn into a beam pointing 20° from broadside. At 12.9 GHz the aperture efficiency is 48%. The second lens acts as a Wollaston-type prism. It splits an incident wave according to its circular polarization components.
147 citations
TL;DR: Results indicate that the relative bandwidth reaches 80% and the efficiency is greater than 88%, thus, ultra-wideband high-efficiency LTC polarization conversion has been realized and the physical mechanism of the polarization conversion is revealed.
Abstract: The polarization conversion of electromagnetic (EM) waves, especially linear-to-circular (LTC) polarization conversion, is of great significance in practical applications. In this study, we propose an ultra-wideband high-efficiency reflective LTC polarization converter based on a metasurface in the terahertz regime. It consists of periodic unit cells, each cell of which is formed by a double split resonant square ring, dielectric layer, and fully reflective gold mirror. In the frequency range of 0.60 - 1.41 THz, the magnitudes of the reflection coefficients reach approximately 0.7, and the phase difference between the two orthogonal electric field components of the reflected wave is close to 90° or -270°. The results indicate that the relative bandwidth reaches 80% and the efficiency is greater than 88%, thus, ultra-wideband high-efficiency LTC polarization conversion has been realized. Finally, the physical mechanism of the polarization conversion is revealed. This converter has potential applications in antenna design, EM measurement, and stealth technology.
146 citations
TL;DR: Quantum dots embedded in the waveguide layer emit circularly polarized light with 25% of circular degree of polarization in on-waveguide semiconductor chiral photonic crystals.
Abstract: We demonstrate circularly polarized light emission from InAs quantum dots embedded in the waveguide region of a GaAs-based chiral nanostructure. The observed phenomenon originates due to a strong imbalance between left- and right-circularly polarized components of the vacuum field and results in a degree of polarization as high as 26% at room temperature. A strong circular anisotropy of the vacuum field modes inside the chiral nanostructure is visualized using numerical simulation. The results of the simulation agree well with experimental results.
145 citations