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 article, an anisotropic metasurface that allows both multiband linear polarization conversion and circular polarization maintaining reflection was proposed, due to the anisotropy of the metamaterial's unit cell.
Abstract: Metasurfaces offer a convenient means to control the polarization state of light. Converting linear polarization (LP) and maintaining circular polarization (CP) in reflection mode have been widely realized, but these two types of polarization control have not been achieved using a single metasurface. This article reports an anisotropic metasurface that allows both multiband LP conversion and CP-maintaining reflection, due to the anisotropy of the metamaterial's unit cell. This system facilitates ultrawide-band polarization converters for $e.g.$ antennas, wireless communication, and radar technology.
70 citations
TL;DR: In ellipsometry of rough surfaces, the commonly used parameters, psi and delta, are insufficient to characterize completely the changes in polarization state which occur when light is reflected from a rough surface.
Abstract: In ellipsometry of rough surfaces, the commonly used parameters, psi and delta, are insufficient to characterize completely the changes in polarization state which occur when light is reflected from a rough surface. When an experimentally determined Mueller matrix is available, parameters indicative of depolarization, cross polarization, and change in ellipticity can be found. When the Mueller matrix is regarded as an operator mapping input polarization states depicted on a Poincare sphere to output states in a similar coordinate system, these new parameters can be illustrated in terms of their effects on the Poincare sphere. The depolarization and cross polarization parameters correlate with specimen roughness and reflectance.
70 citations
Patent•
22 May 2002TL;DR: In this paper, a plate fabricated from birefringent material on whose entrance and exit faces small zones with deflecting structures in the form of gratings or Fresnel surfaces has been created.
Abstract: A polarizer suitable for transforming incident linearly polarized or circularly polarized light into exiting radially or tangentially polarized light with virtually no transmission losses has, in one of its embodiments, a plate fabricated from birefringent material on whose entrance and exit faces small zones ( 11, 12 ) with deflecting structures ( 8, 9 ) in the form of gratings or Fresnel surfaces have been created. The crystal axis ( 5 ) of said birefringent material is aligned parallel to the incident light beam. Said deflecting structures deflect light along a transmission direction ( 13 ) that is inclined with respect to said crystal axis ( 5 ), causing a phase shift between the field components of the transmitted light. Suitable choices of the angle of inclination (NW) of said transmission direction with respect to said crystal axis and the thickness (D) of said plate will allow transforming incident linearly polarized or circularly polarized light into an exiting light beam with an axisymmetric (tangential or radial) polarization distribution.
69 citations
TL;DR: In this paper, a dual circularly polarized (CP) array antenna is presented for Ka-band wireless communication, where a triple-resonant cavity is proposed to implement mode conversion and impedance matching in the $2 \times 2$ -element subarray.
Abstract: A dual circularly polarized (CP) waveguide array antenna is presented for Ka-band wireless communication. A novel triple-resonant cavity is proposed to implement mode conversion and impedance matching in the $2 \times 2$ -element subarray. A ridge waveguide polarizer is integrated to form the left-hand circular polarization (LHCP) and the right-hand circular polarization (RHCP). A flyover-shaped full-corporate feeding network is designed to accommodate the dual polarizations and keep the wideband characteristic for a large-scale array. Subarray spacing is used to optimize the port-to-port isolation and decrease the sidelobe level at some definite angles. Computer numerically controlled machining technology is applied to fabricating a $16 \times 16$ -element prototype. Measured results demonstrate a bandwidth of 16% from 27.6 to 32.4 GHz for the dual polarizations, in terms of good reflection coefficient and axial ratio. A maximum gain of 32.8 dBic is achieved at 28.8 GHz. A total efficiency over 60% is obtained throughout the above band for both LHCP and RHCP ports.
69 citations
TL;DR: It is shown that by introducing a polarization modulation that does not give rise to a change in the optical rotation it is possible to differentiate between the two circular polarization components even after post-selection with a linear polarizer.
Abstract: We present a new form of optical activity measurement based on a modified weak value amplification scheme. It has recently been shown experimentally that the left- and right-circular polarization components refract with slightly different angles of refraction at a chiral interface causing a linearly polarized light beam to split into two. By introducing a polarization modulation that does not give rise to a change in the optical rotation it is possible to differentiate between the two circular polarization components even after post-selection with a linear polarizer. We show that such a modified weak value amplification measurement permits the sign of the splitting and thus the handedness of the optically active medium to be determined. Angular beam separations of Δθ ∼ 1 nanoradian, which corresponds to a circular birefringence of Δn ∼ 1 × 10(-9), could be measured with a relative error of less than 1%.
69 citations