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: In this paper, the authors present explicit expressions for these observables for the simple case of light scattered at an arbitrary angle in incident light perpendicular to the surface with the molecules restricted to a unique orientation relative to surface normal but with free rotation about the normal in the plane of the surface.
102 citations
TL;DR: A metal/phase-change material/metal tri-layer planar chiral metamaterial in the shape of a gammadion is numerically modelled to accomplish a wide tuning range of the circular dichroism in the mid-infrared wavelength regime.
Abstract: A metal/phase-change material/metal tri-layer planar chiral metamaterial in the shape of a gammadion is numerically modelled. The chiral metamaterial is integrated with Ge2Sb2Te5 phase-change material (PCM) to accomplish a wide tuning range of the circular dichroism (CD) in the mid-infrared wavelength regime. A photothermal model is used to study the temporal variation of the temperature of the Ge2Sb2Te5 layer and to show the potential for fast switching the phase of Ge2Sb2Te5 under a low incident light intensity of 0.016mW/μm2.
102 citations
TL;DR: In this article, the authors presented five epochs of 15 GHz VLBA observations of 13 AGNs and used them to detect parsec-scale circular polarization at the level of approximately 0.3% to 1% local fractional circular polarization.
Abstract: We present five epochs of 15 GHz VLBA observations of 13 AGNs. These observations were specially calibrated to detect parsec-scale circular polarization and our calibration techniques are discussed and analyzed in detail. We obtained reliable detections of parsec-scale circular polarization in the radio jets of four AGNs: 3C 84, PKS 0528+134, 3C 273, and 3C 279. For each of these objects our detections are at the level of approximately 0.3%–1% local fractional circular polarization. Each individual detection has a significance in the range of 3 to 10 σ. Our observations are consistent across multiple epochs (and different calibration techniques) in the sign and magnitude of the circular polarization observed. 3C 273 and 3C 279 both undergo core outbursts during our observations and changes in the circular polarization of both sources are correlated with these outbursts. In general, we observe the circular polarization to be nearly coincident with the strong VLBI cores of these objects; however, in 3C 84 the circular polarization is located a full milliarcsecond south of the source peak, and in the 1996.73 epoch of 3C 273 the circular polarization is predominately associated with the newly emerging jet component. Our observations support the theoretical conclusion that emission of circular polarization is a sensitive function of opacity, being strongest when the optical depth is near unity. Circular polarization may be produced as an intrinsic component of synchrotron radiation or by the Faraday conversion of linear to circular polarization. Our single-frequency observations do not easily distinguish between these possible mechanisms, but independent of mechanism, the remarkable consistency across epoch of the sign of the observed circular polarization suggests the existence of a long-term, stable, unidirectional magnetic field. Single-dish observations of 3C 273 and 3C 279 at 8 GHz by Hodge and Aller suggest that this stability may persist for decades in our frame of observation.
102 citations
TL;DR: In this paper, an expression for optical visibility during storms is given in terms of the relative volume occupied by dust, and expressions for attenuation and phase shift constants for a medium with precipitating dust particles are derived in terms both of visibility and wavelength for both vertical and horizontal polarizations.
Abstract: Some of the electrical and mechanical properties of dust are discussed. An expression for optical visibility during storms is given in terms of the relative volume occupied by dust. Expressions for attenuation and phase shift constants for a medium with precipitating dust particles are derived in terms of visibility and wavelength for both vertical and horizontal polarizations. Expressions for the attenuation and cross polarization of circularly polarized waves are also derived. Computations show that linearly polarized waves suffer but little effect. Circularly polarized waves on the other hand are significantly cross polarized.
102 citations
TL;DR: In this article, a rectangular dielectric resonator antenna (DRA) with a single slot feed was proposed to generate circular polarisation with a low axial ratio over a wide frequency band and a wide beamwidth.
Abstract: A rectangular dielectric resonator antenna (DRA) which produces circular polarisation with a single slot feed is investigated. The antenna element uses mutually orthogonal nearly degenerate modes to generate circular polarisation with a low axial ratio over a wide frequency band and a wide beamwidth.
101 citations