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The electronic structures and ferroelectric properties of barium fluoride BaZnF4were investigated by employing ab initio calculations based on the density-functional theory within generalized gradient approximation. We discussed t...
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The electronic structures and ferroelectric properties of barium fluoride BaZnF4were investigated by employing ab initio calculations based on the density-functional theory within generalized gradient approximation. We discussed the possible origin of ferroelectricity of BaZnF4 by the analysis of Born effective charges, orbital-resolved density of states, and distribution of charge density. The results show that the barium and fluorine atoms are very important polarization unity. The calculated spontaneous polarization of 14.2 UC/cm2 by using Berry-phase approach is reasonable agreement with previous experimental data. Barium fluorides are promising candidates for use in nonvolatile memories devices.
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The polarization of light has been studied for more than two centuries, and most people have heard of polarized sunglasses- an 80-year-old invention. Yet engineering the polarization properties of guided waves in integrated photon...
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The polarization of light has been studied for more than two centuries, and most people have heard of polarized sunglasses- an 80-year-old invention. Yet engineering the polarization properties of guided waves in integrated photonic devices is not easy, as optical waveguides are not generally sensitive to polarization.
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While halide perovskites (HPs) have achieved enormous success in the field of optoelectronic applications, much attention has been recently drawn to the unique polarization sensitivity of HPs, either intrinsic or extrinsic, which ...
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While halide perovskites (HPs) have achieved enormous success in the field of optoelectronic applications, much attention has been recently drawn to the unique polarization sensitivity of HPs, either intrinsic or extrinsic, which makes HPs a potential candidate for innovative applications in directly polarized luminescence and detection. Herein, the research status in the field of polarization-sensitive HPs, including linear polarization and circular polarization, is comprehensively summarized. To evaluate the effectiveness of HPs in generating and detecting linearly or circularly polarized light, the principles and characterization methods of polarized luminescence and detection are introduced. Sequentially, the state-of-the-art development of the strategies that induce the linear or circular polarization characteristics of HPs is systematically reviewed, based on which the application of polarization-sensitive HPs in the field of polarization luminescence and detection are summarized. Moreover, the current challenges and opportunities are discussed, and prospects of the future development in this promising field are outlined.
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Polarized Small Angle Neutron Scattering (SANS) is a powerful tool for studying mesoscale magnetic structures. In a recent development at the Oak Ridge National Laboratory (ORNL), a polarized neutron beam has been implemented for ...
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Polarized Small Angle Neutron Scattering (SANS) is a powerful tool for studying mesoscale magnetic structures. In a recent development at the Oak Ridge National Laboratory (ORNL), a polarized neutron beam has been implemented for the CG-2 (GP-SANS) beamline at the High Flux Isotope Reactor (HFIR). Three major components were developed to provide the polarized neutron capability: a transmission supermirror neutron polarizer, an adiabatic fast passage neutron spin flipper and a polarized He-3 filter as neutron spin analyzer. The new polarized beam SANS capability was used to investigate several magnetic samples having mesoscale structures.
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A multilayer comprising birefringent thin films is devised to present to function as a polarization beam splitter and waveplate simultaneously. By arranging such a multilayer on a right triangle-shaped corrugated surface, a polari...
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A multilayer comprising birefringent thin films is devised to present to function as a polarization beam splitter and waveplate simultaneously. By arranging such a multilayer on a right triangle-shaped corrugated surface, a polarizer is realized to align the randomly oscillating electric field of an unpolarized wave into a linear polarized wave without loss.
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In this work, first the necessary conditions for a versatile cross-polarization conversion meta-atom that operates both for linear and circular cross polarizations are discussed. Based on these, a versatile chiral metasurface cros...
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In this work, first the necessary conditions for a versatile cross-polarization conversion meta-atom that operates both for linear and circular cross polarizations are discussed. Based on these, a versatile chiral metasurface cross-polarization converter is proposed. The correspondence between its physical geometry and polarization domain characteristics is studied. To verify the design concept, a prototype is fabricated and measured. An effective vertical and horizontal linear cross-polarization conversion is achieved from 29.3 to 38.8 GHz (27.90%) and from 34.0 to 36.6 GHz (7.36%), respectively. Furthermore, the proposed converter also achieves circular polarization handedness rotation from 34.5 to 36.6 GHz (5.91%).
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A novel source of polarized hydrogen and deuterium molecules has been tested. The use of sextupole superconducting magnets allows us to select molecules with the nuclear spin projection -1 for hydrogen and -2 for deuterium. The me...
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A novel source of polarized hydrogen and deuterium molecules has been tested. The use of sextupole superconducting magnets allows us to select molecules with the nuclear spin projection -1 for hydrogen and -2 for deuterium. The measured beam intensity of polarized hydrogen molecules for the nozzle temperature range of 6.5-30 K and a gas flow rate up to 5 · 10~(-2) Torr • 1/s is presented. The measured flux of polarized hydrogen molecules of ≈ 3 • 10~(12) mol/s is in reasonable agreement with estimations. The obtained results can be used as a basis for the development of a high-intensity source of polarized molecules.
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A novel approach, an optical radio over fiber link with double polarization multiplexing is presented. In the two orthogonal polarizations of the optical beam the contents of information to be transmitted are different doubling th...
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A novel approach, an optical radio over fiber link with double polarization multiplexing is presented. In the two orthogonal polarizations of the optical beam the contents of information to be transmitted are different doubling the link capacity this way. For experimental verification a millimeter wave radio over fiber link with double polarization multiplexing has been developed. To ensure low cross polarization an incoherent approach is used. A high quality signal transmission is achieved by a proper procedure providing high polarization extinction ratio. In the experimental investigations different bit rates and fiber lengths are used. A signal with 12 Gbit/s bit rate is transmitted over a 25 km long link with about 1.10~(-8) bit error rate. That result is much better than the already published data measured on experimental links.
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In this paper, we discuss a potential multiple access and modulation scheme based on polarized states (PS) of electromagnetic (EM) waves for line-of-sight (LOS) communications. The proposed scheme is theoretic different from the e...
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In this paper, we discuss a potential multiple access and modulation scheme based on polarized states (PS) of electromagnetic (EM) waves for line-of-sight (LOS) communications. The proposed scheme is theoretic different from the existing polar modulation for EDGE and WCDMA systems. We propose the detailed bit representation (modulation) and multiple access scheme using PS. Because of the inflexibility of polarization information in the time and frequency domains, as well as independence of frequency and space, the polarization information can be used independently for wireless communications, i.e., another independent resource domain that can be utilized. Due to the independence between the PS and the specific features of signals (such as waveform, bandwidth and data rate), the discussed polarization division multiple access (PDMA) and polarization modulation (PM) are expected to improve the spectrum utilization effectively. It is proved that the polarization filtering technique can be adopted in the PDMA-PM wireless communications to separate the multiuser signals and demodulate the bit information representing by PS for desired user. Some theoretical analysis is done to demonstrate the feasibility of the proposed scheme, and the simulation results are made to evaluate the performance of the suggested system.
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The conductive and capacitive material properties of the subsurface can be quantified through the frequency-dependent complex resistivity. However, the routine three-dimensional (3D) interpretation of voluminous induced polarizati...
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The conductive and capacitive material properties of the subsurface can be quantified through the frequency-dependent complex resistivity. However, the routine three-dimensional (3D) interpretation of voluminous induced polarization (IP) data sets still poses a challenge due to large computational demands and solution nonuniqueness. We have developed a flexible methodology for 3D (spectral) IP data inversion. Our inversion algorithm is adapted from a frequency-domain electromagnetic (EM) inversion method primarily developed for large-scale hydrocarbon and geothermal energy exploration purposes. The method has proven to be efficient by implementing the nonlinear conjugate gradient method with hierarchical parallelism and by using an optimal finite-difference forward modeling mesh design scheme. The method allows for a large range of survey scales, providing a tool for both exploration and environmental applications. We experimented with an image focusing technique to improve the poor depth resolution of surface data sets with small survey spreads. The algorithm's underlying forward modeling operator properly accounts for EM coupling effects; thus, traditionally used EM coupling correction procedures are not needed. The methodology was applied to both synthetic and field data. We tested the benefit of directly inverting EM coupling contaminated data using a synthetic largescale exploration data set. Afterward, we further tested the monitoring capability of our method by inverting timelapse data from an environmental remediation experiment near Rifle, Colorado. Similar trends observed in both our solution and another 2D inversion were in accordance with previous findings about the IP effects due to subsurface microbial activity.
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