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 transverse spin component, orthogonal to the main propagation direction, is shown to survive even in non-paraxial fields (e.g., tightly focused or evanescent) generated from a totally unpolarized light source.
Abstract: It is well known that spin angular momentum of light, and therefore that of photons, is directly related to their circular polarization. Naturally, for totally unpolarized light, polarization is undefined and the spin vanishes. However, for nonparaxial light, the recently discovered transverse spin component, orthogonal to the main propagation direction, is largely independent of the polarization state of the wave. Here we demonstrate, both theoretically and experimentally, that this transverse spin survives even in nonparaxial fields (e.g., tightly focused or evanescent) generated from a totally unpolarized light source. This counterintuitive phenomenon is closely related to the fundamental difference between the degrees of polarization for 2D paraxial and 3D nonparaxial fields. Our results open an avenue for studies of spin-related phenomena and optical manipulation using unpolarized light.
64 citations
TL;DR: A high transparency of metasurface-based polarization controller at microwave frequencies, which consists of orthogonal two pairs of cut wires, which is ultrathin (~0.017λ), as opposed to bulky polarization devices.
Abstract: We proposed, designed and fabricated a high transparency of metasurface-based polarization controller at microwave frequencies, which consists of orthogonal two pairs of cut wires. The high transmission and the strong dispersion properties governed by electromagnetically induced transparency-like (EIT-like) effects for both incident polarizations make our device efficiently manipulating the polarization of EM waves. In particular, the proposed polarization device is ultrathin (~0.017λ), as opposed to bulky polarization devices. Microwave experiments are performed to successfully demonstrate our ideas, and measured results are in reasonable agreement with numerical simulations.
64 citations
TL;DR: In this article, the authors demonstrate cumulative magnetization switching in granular Fe-Pt-C due to multiple pulses of circularly polarized light, which shows that this form of AOS can aid writing in a heat-assisted magnetic recording (HAMR) like recording process.
Abstract: In addition to heat-assisted magnetic recording (HAMR), all-optical switching (AOS) is an attractive technology for the next generation of ultrahigh-density, ultrafast, ultralow-power digital storage. The authors demonstrate cumulative magnetization switching in granular Fe-Pt-C due to multiple pulses of circularly polarized light. While this base process is statistical, adding a modest external magnetic field allows deterministic switching, which shows that this form of AOS can aid writing in a HAMR-like recording process.
64 citations
TL;DR: The first measurement of dual circular polarization (DCP) Raman optical activity (ROA) was reported in this article, where the incident and scattered light beams are synchronously modulated between right and left circular polarization states.
64 citations
19 May 2005
TL;DR: In this article, a novel polarimetric millimeter-wave imaging technique has been developed at the Pacific Northwest National Laboratory (PNNL) for concealed weapon detection applications, where three-dimensional images are formed using computer image reconstruction algorithms developed to mathematically focus the received wavefronts scattered from the target.
Abstract: A novel polarimetric millimeter-wave imaging technique has been developed at the Pacific Northwest National Laboratory (PNNL) for concealed weapon detection applications. Wideband millimeter-wave imaging systems developed at PNNL utilize low-power, coherent, millimeter-wave illumination in the 10-100 GHz range to form high-resolution images of personnel. Electromagnetic waves in these frequency ranges easily penetrate most clothing materials and are reflected from the body and any concealed items. Three-dimensional images are formed using computer image reconstruction algorithms developed to mathematically focus the received wavefronts scattered from the target. Circular polarimetric imaging can be employed to obtain additional information from the target. Circularly polarized waves incident on relatively smooth reflecting targets are typically reversed in their rotational handedness, e.g. left-hand circular polarization (LHCP) is reflected to become right-hand circular polarization (RHCP). An incident wave that is reflected twice (or any even number) of times prior to returning to the transceiver, has its handedness preserved. Sharp features such as wires and edges tend to return linear polarization, which can be considered to be a sum of both LHCP and RHCP. These characteristics can be exploited for personnel screening by allowing differentiation of smooth features, such as the body, and sharper features present in many concealed items. Additionally, imaging artifacts due to multipath can be identified and eliminated. Laboratory imaging results have been obtained in the 10-20 GHz frequency range and are presented in this paper.
64 citations