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Optical polarization
About: Optical polarization is a research topic. Over the lifetime, 13992 publications have been published within this topic receiving 244284 citations.
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TL;DR: In this article, a grating waveguide is designed to serve as both a polarization splitter and an efficient vertical coupler between a fiber and a silicon-on-insulator (SOI) nanophotonic waveguide.
Abstract: A grating waveguide is introduced and designed to serve as both a polarization splitter and an efficient vertical coupler between a fiber and a silicon-on-insulator (SOI) nanophotonic waveguide. Through this grating waveguide, the light from the fiber can be efficiently coupled into an SOI chip where the two orthogonally polarized waves are separated to travel towards the opposite directions along the waveguide. According to our simulations, the optimized structure can give a high coupling efficiency of about 50% for both polarizations, as well as a large bandwidth of over 70 nm and a very low polarization crosstalk below -22 dB at the output ports.
87 citations
TL;DR: In this article, a high-speed long-distance wireless transmission link at W-band based on some enabling technologies and advanced devices, such as antenna polarization multiplexing combined with multiple-input multiple-output, large-gain/high-power Wband electrical amplifiers, high-gain small-beamwidth Cassegrain antennas, and wideband optical/electrical components, is proposed.
Abstract: W-band (75–110 GHz) is a potential radio frequency band to provide long-distance wireless links for mobile data transmission. We proposed a high-speed long-distance wireless transmission link at W-band based on some enabling technologies and advanced devices, such as antenna polarization multiplexing combined with multiple-input multiple-output, large-gain/high-power W-band electrical amplifiers, high-gain small-beamwidth Cassegrain antennas, and wideband optical/electrical components. We experimentally demonstrated that our proposed wireless transmission link can realize up to 1.7-km wireless delivery of 20-Gb/s@85.5-GHz millimeter-wave signal with a bit-error rate less than $3.8 \times 10^{-3}$ .
87 citations
TL;DR: In this article, the authors review experimental results on transition-metal doping of ZnO and the current state of theories for ferromagnetic second phases in the material and conclude that the spin device appears to have no advantage relative to the conventional charge-control electronic analog.
Abstract: ZnO is an attractive candidate for spintronics studies because of its potential for exhibiting high Curie temperatures and the relative lack of ferromagnetic second phases in the material. In this paper, we review experimental results on transition-metal (TM) doping of ZnO and the current state of theories for ferromagnetism. It is important to re-examine some of the earlier concepts for spintronics devices, such as the spin field-effect transistor, to account for the presence of the strong magnetic field that has deleterious effects. In some of these cases, the spin device appears to have no advantage relative to the conventional charge-control electronic analog. We have been unable to detect optical spin polarization in ZnO.
87 citations
TL;DR: The measured PSM of these components in an optical system is very close to the theoretically predicted values, thus showing that these components should provide excellent performance in applications utilizing polarized optical vortices.
Abstract: We present developments using photoaligned liquid crystal polymers for creating vortex retarders, half-wave retarders with a continuously variable fast axis. Polarization properties of components designed to create different polarization vortex modes are presented. We assess the viability of these components by using the theoretical and experimental point spread functions in Mueller matrix format, or a point spread matrix (PSM). The measured PSM of these components in an optical system is very close to the theoretically predicted values, thus showing that these components should provide excellent performance in applications utilizing polarized optical vortices.
87 citations
TL;DR: In this article, the radio source OV236 (1921-293) has been classified both as a quasar and a flat-spectrum radio source and its polarization and variability at 2.2 µm1 and generally featureless optical spectrum are consistent with it being a BL Lac object.
Abstract: As part of a programme of multifrequency single epoch observations of BL Lac objects and flat-spectrum radio sources we have examined the radio source OV236 (1921–293) which has been classified both as a quasar and a BL Lac object. Its polarization and variability at 2.2 µm1 and generally featureless optical spectrum are consistent with it being a BL Lac object. Wills and Wills2 measured its optical polarization, variability and emission line spectrum and find it to have a redshift z = 0.352. It is an extremely variable radio source, during the outburst reported by Dent and Balonek3 it was the brightest 10-cm quasar in the sky. The outburst was first measured at 3.3 mm and was increasingly delayed at longer wavelengths; there was also evidence for correlated optical/radio variability during this outburst4. We have obtained J, H, K, 10, 20, 800 and 1,100 µm flux measurements of 1921–293 over a period of four days from the same telescope, enabling us to present a ‘snapshot’ of its IR to millimetre spectrum. The continuum spectrum of 1921–293 is suggestive of a peak in the submillimetre region. This excess could be due to an injection of high-energy electrons into a synchrotron emitting region, although thermal emission from dust remains a possibility.
87 citations