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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Patent•
17 Jun 1998
TL;DR: In this paper, a phased array antenna with stacked-disc radiators embedded in dielectric media is shown to have a rectangular arrangement of unit cells that are disposed on a ground plane.
Abstract: A phased array antenna (10) having stacked-disc radiators embedded in dielectric media. The phased array antenna has a rectangular arrangement of unit cells (19) that are disposed on a ground plane (11). A lower dielectric puck (12) with a high dielectric constant is disposed on the ground plane. An excitable disc (13) is disposed within the perimeter of and on top of the lower dielectric puck. An upper low dielectric constant dielectric puck (16) that has a dielectric constant lower than that of the lower dielectric puck is disposed on the excitable disc. A parasitic disc (17) is disposed within the perimeter of and on top of the upper dielectric puck. Dielectric filler material (26) having a dielectric constant that is lower than that of the lower dielectric puck surrounds the dielectric pucks. A radome (18) is disposed on top of the parasitic disc and the unit cell. Two orthogonal pairs of excitation probes (14) are coupled to the lower excitable disc. The polarization of the phased array antenna may be single linear polarization, dual linear polarization, or circular polarization depending on whether a single pair or two pairs of excitation probes are excited
67 citations
TL;DR: A 220 diamond phase plate was combined with an energy-dispersive absorption spectrometer to convert linearly polarized X-rays into circularly polarized photons and to detect circular magnetic X-ray dichroism (CMXD) from ferromagnetic samples as mentioned in this paper.
Abstract: A 220 diamond phase plate was combined with an energy-dispersive absorption spectrometer to convert linearly polarized X-rays into circularly polarized photons and to detect circular magnetic X-ray dichroism (CMXD) from ferromagnetic samples. In these experiments, carried out at LURE, the energy-dispersive spectrometer was equipped with a bent Si (311) polychromator and vertically collimating slits accepting essentially a linearly polarized incident beam. The quarter-wave plate was operated in the Bragg geometry but well outside the range of quasi total reflection, with the consequence that the forward-diffracted beam was circularly polarized with a polarization rate approaching 80% over the whole energy bandpass of the polychromator. CMXD spectra of GdFe2 and GdCo2 intermetallic compounds were recorded at ca 7.2 keV near the Gd LIII absorption edge: they are essentially identical to the spectra commonly recorded with elliptically polarized X-ray photons collected out of the orbit plane of the storage ring. It is suggested that the energy-dispersive phase plate will be very useful to detect CMXD spectra with energy-dispersive spectrometers exploiting the well collimated linearly polarized emission of standard undulators installed on the storage rings of the third generation.
67 citations
TL;DR: In this paper, a dual-pump all-optical wavelength conversion based on a four-wave mixing (FWM) in a high-nonlinear dispersion shifted fiber (HNL-DSF) is demonstrated experimentally.
Abstract: The dual-pump all-optical wavelength conversion based on a four-wave mixing (FWM) in a high-nonlinear dispersion shifted fiber (HNL-DSF) is demonstrated experimentally. The polarization sensitivity of the wavelength converter based on this dual-pump figuration is investigated experimentally and theoretically. The experimental results indicate that the wavelength-conversion configuration with copolarization pumps shows the smallest polarization sensitivity. A model of the beating-wave modulation from the dynamic wave equation is erected to explain the experimental phenomena, and the theoretical analyses agree well with the experimental results.
67 citations
TL;DR: In this paper, the spin polarization of InAs∕GaAs self-assembled quantum dots (QDs) at room temperature was investigated and the results demonstrated that practical regimes of spin-based operation are clearly attainable in solid-state semiconductor devices.
Abstract: We report on electrical control of the spin polarization of InAs∕GaAs self-assembled quantum dots (QDs) at room temperature. This is achieved by electrical injection of spin-polarized electrons from an Fe Schottky contact. The circular polarization of the QD electroluminescence shows that a 5% electron spin polarization is obtained in the InAs QDs at 300K, which is remarkably insensitive to temperature. This is attributed to suppression of the spin-relaxation mechanisms in the QDs due to reduced dimensionality. These results demonstrate that practical regimes of spin-based operation are clearly attainable in solid-state semiconductor devices.
67 citations
TL;DR: In this paper, the decay of a circularly polarized electromagnetic wave propagating parallel to an external magnetic field into another LME and an ion acoustic wave in a homogeneous plasma is considered.
Abstract: The decay of a circularly polarized electromagnetic wave propagating parallel to an external magnetic field into another circularly polarized electromagnetic wave and an ion acoustic wave in a homogeneous plasma is considered.
67 citations