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Showing papers on "Circular polarization published in 2022"


Journal ArticleDOI
09 Sep 2022-Science
TL;DR: Zhang et al. as mentioned in this paper used the physics of chiral quasi-bound states in the continuum to demonstrate the efficient and controllable emission of circularly polarized light from resonant metasurfaces.
Abstract: Ultracompact sources of circularly polarized light are important for classical and quantum optical information processing. Conventional approaches for generating chiral emission are restricted to excitation power ranges and fail to provide high-quality radiation with perfect polarization conversion. We used the physics of chiral quasi-bound states in the continuum to demonstrate the efficient and controllable emission of circularly polarized light from resonant metasurfaces. Exploiting intrinsic chirality and giant field enhancement, we revealed how to simultaneously modify and control spectra, radiation patterns, and spin angular momentum of photoluminescence and lasing without any spin injection. The superior characteristics of chiral emission and lasing promise multiple applications in nanophotonics and quantum optics. Description Another twist for metasurfaces Metasurfaces are specially designed arrays of dielectric components that transform the function of bulk optical components into thin films. Exploiting the physics of bulk states in the continuum for the highly efficient trapping of light, Zhang et al. demonstrate metasurfaces that operate as a source of chiral light (see the Perspective by Forbes). Using a dielectric metasurface doped with light-emitting molecules, they were able to produce chiral photoluminescence and lasing. This approach will be useful for the development of integrated optical devices. —ISO Cobalt carbonyl catalysts prove stable at lower gas pressure than previously thought.

60 citations


Journal ArticleDOI
TL;DR: In this article , an efficient strategy to achieve multicolor CPOA molecules through chiral clusterization by implanting chirality center into non-conjugated organic cluster was reported.
Abstract: Abstract Circularly polarized organic afterglow (CPOA) with both long-lived room-temperature phosphorescence (RTP) and circularly polarized luminescence (CPL) is currently attracting great interest, but the development of multicolor-tunable CPOA in a single-component material remains a formidable challenge. Here, we report an efficient strategy to achieve multicolor CPOA molecules through chiral clusterization by implanting chirality center into non-conjugated organic cluster. Owing to excitation-dependent emission of clusters, highly efficient and significantly tuned CPOA emissions from blue to yellowish-green with dissymmetry factor over 2.3 × 10 −3 and lifetime up to 587 ms are observed under different excitation wavelengths. With the distinguished color-tunable CPOA, the multicolor CPL displays and visual RTP detection of ultraviolent light wavelength are successfully constructed. These results not only provide a new paradigm for realization of multicolor-tunable CPOA materials in single-component molecular systems, but also offer new opportunities for expanding the applicability of CPL and RTP materials for diversified applications.

46 citations


Journal ArticleDOI
TL;DR: In this article , a single-handed circular polarization (CP) conversion using dynamic phase was obtained in the terahertz (THz) band using a silicon-based metalens.
Abstract: If a metalens integrates the circular polarization (CP) conversion function, the focusing lens together with circular-polarizing lens (CPL) in traditional cameras may be replaced by a metalens. However, in terahertz (THz) band, the reported metalenses still do not obtain the perfect and strict single-handed CP, because they were constructed via Pancharatnam-Berry phase so that CP conversion contained both left-handed CP (LCP) and right-handed CP (RCP) components. In this paper, a silicon based THz metalens is constructed using dynamic phase to obtain single-handed CP conversion. Also, we can rotate the whole metalens at a certain angle to control the conversion of multi-polarization states, which can simply manipulate the focusing for incident linear polarization (LP) THz wave in three polarization conversion states, including LP without conversion, LCP and RCP. Moreover, the polarization conversion behavior is reversible, that is, the THz metalens can convert not only the LP into arbitrary single-handed CP, but also the LCP and RCP into two perpendicular LP, respectively. The metalens is expected to be used in advanced THz camera, as a great candidate for traditional CPL and focusing lens group, and also shows potential application in polarization imaging with discriminating LCP and RCP.

45 citations


Journal ArticleDOI
TL;DR: In this paper , an efficient strategy to achieve multicolor CPOA molecules through chiral clusterization by implanting chirality center into non-conjugated organic cluster was reported.
Abstract: Abstract Circularly polarized organic afterglow (CPOA) with both long-lived room-temperature phosphorescence (RTP) and circularly polarized luminescence (CPL) is currently attracting great interest, but the development of multicolor-tunable CPOA in a single-component material remains a formidable challenge. Here, we report an efficient strategy to achieve multicolor CPOA molecules through chiral clusterization by implanting chirality center into non-conjugated organic cluster. Owing to excitation-dependent emission of clusters, highly efficient and significantly tuned CPOA emissions from blue to yellowish-green with dissymmetry factor over 2.3 × 10 −3 and lifetime up to 587 ms are observed under different excitation wavelengths. With the distinguished color-tunable CPOA, the multicolor CPL displays and visual RTP detection of ultraviolent light wavelength are successfully constructed. These results not only provide a new paradigm for realization of multicolor-tunable CPOA materials in single-component molecular systems, but also offer new opportunities for expanding the applicability of CPL and RTP materials for diversified applications.

43 citations


Journal ArticleDOI
TL;DR: In this article , the symmetry-reduced meta-atoms with high birefringence supporting winding elliptical eigenstate polarizations with opposite helicity were employed to achieve the maximal planar chirality tuned by either breaking inplane structure symmetry or changing illumination angle.
Abstract: Abstract Optical metasurfaces with high quality factors (Q-factors) of chiral resonances can boost substantially light-matter interaction for various applications of chiral response in ultrathin, active, and nonlinear metadevices. However, current approaches lack the flexibility to enhance and tune the chirality and Q-factor simultaneously. Here, we suggest a design of chiral metasurface supporting bound state in the continuum (BIC) and demonstrate experimentally chiroptical responses with ultra-high Q-factors and near-perfect circular dichroism (CD = 0.93) at optical frequencies. We employ the symmetry-reduced meta-atoms with high birefringence supporting winding elliptical eigenstate polarizations with opposite helicity. It provides a convenient way for achieving the maximal planar chirality tuned by either breaking in-plane structure symmetry or changing illumination angle. Beyond linear CD, we also achieved strong near-field enhancement CD and near-unitary nonlinear CD in the same planar chiral metasurface design with circular eigen-polarization. Sharply resonant chirality realized in planar metasurfaces promises various practical applications including chiral lasers and chiral nonlinear filters.

43 citations


Journal ArticleDOI
TL;DR: These findings are expected to guide development of CPLE materials in a variety of technological fields, including 3D displays, information storage, biosensors, optical spintronics, and biological probes.
Abstract: Chiral inorganic nanostructures strongly interact with photons changing their polarization state. The resulting circularly polarized light emission (CPLE) has cross-disciplinary importance for a variety of chemical/biological processes and is essential for development of chiral photonics. However, the polarization effects are often complex and could be misinterpreted. CPLE in nanostructured media has multiple origins and several optical effects are typically convoluted into a single output. Analysing CPLE data obtained for nanoclusters, NPs, nanoassemblies, and nanocomposites from metals, chalcogenides, perovskite, and other nanostructures, we show that there are several distinct groups of nanomaterials for which CPLE is dominated either by circularly polarized luminescence (CPL) or circularly polarized scattering (CPS); there are also many nanomaterials for which they are comparable. We also show that (1) CPL and CPS contributions involve light-matter interactions at different structural levels; (2) contribution from CPS is especially strong for nanostructured microparticles, nanoassemblies and composites; and (3) engineering of materials with strongly polarized light emission requires synergistic implementation of CPL and CPS effects. These findings are expected to guide development of CPLE materials in a variety of technological fields, including 3D displays, information storage, biosensors, optical spintronics, and biological probes. This article is protected by copyright. All rights reserved.

40 citations


Journal ArticleDOI
TL;DR: Based on the Pancharatnam-Berry phase principle, the unit cells with the cross-circular polarization gradient phase were carefully designed and constructed into a metasurface as discussed by the authors .
Abstract: In view of the fact that most invisibility devices focus on linear polarization cloaking and that the characteristics of mid-infrared cloaking are rarely studied, we propose a cross-circularly polarized invisibility carpet cloaking device in the mid-infrared band. Based on the Pancharatnam-Berry phase principle, the unit cells with the cross-circular polarization gradient phase were carefully designed and constructed into a metasurface. In order to achieve tunable cross-circular polarization carpet cloaks, a phase change material is introduced into the design of the unit structure. When the phase change material is in amorphous and crystalline states, the proposed metasurface unit cells can achieve high-efficiency cross-polarization conversion, and reflection intensity can be tuned. According to the phase compensation principle of carpet cloaking, we construct a metasurface cloaking device with a phase gradient using the designed unit structure. From the near- and far-field distributions, the cross-circular polarization cloaking property is confirmed in the broadband wavelength range of 9.3–11.4 µm. The proposed cloaking device can effectively resist detection of cross-circular polarization.

40 citations


Journal ArticleDOI
TL;DR: In this article , it was shown that nanoporous thin films of chiral nanoparticles enable high sensitivity to circular polarization due to light-induced polarization-dependent ion accumulation at nanoparticle interfaces.
Abstract: Optoelectronic effects differentiating absorption of right and left circularly polarized photons in thin films of chiral materials are typically prohibitively small for their direct photocurrent observation. Chiral metasurfaces increase the electronic sensitivity to circular polarization, but their out-of-plane architecture entails manufacturing and performance trade-offs. Here, we show that nanoporous thin films of chiral nanoparticles enable high sensitivity to circular polarization due to light-induced polarization-dependent ion accumulation at nanoparticle interfaces. Self-assembled multilayers of gold nanoparticles modified with L-phenylalanine generate a photocurrent under right-handed circularly polarized light as high as 2.41 times higher than under left-handed circularly polarized light. The strong plasmonic coupling between the multiple nanoparticles producing planar chiroplasmonic modes facilitates the ejection of electrons, whose entrapment at the membrane-electrolyte interface is promoted by a thick layer of enantiopure phenylalanine. Demonstrated detection of light ellipticity with equal sensitivity at all incident angles mimics phenomenological aspects of polarization vision in marine animals. The simplicity of self-assembly and sensitivity of polarization detection found in optoionic membranes opens the door to a family of miniaturized fluidic devices for chiral photonics.

38 citations


Journal ArticleDOI
10 Feb 2022-ACS Nano
TL;DR: In this paper , the chiral spacers of two-dimensional (2D) lead halide perovskites (LHPs) enable them to exhibit circularly polarized photoluminescence (CPPL), which could have applications in chiral-optics and spintronics.
Abstract: Introducing the chiral spacers to two-dimensional (2D) lead halide perovskites (LHPs) enables them to exhibit circularly polarized photoluminescence (CPPL), which could have applications in chiral-optics and spintronics. Despite that a great deal of effort has been made in this field, the reported polarization degree of CPPL at ambient conditions is still very limited, and the integration of multiple functionalities also remains to be explored. Here we report the structures, CPPL, and piezoelectric energy harvesting properties of chiral 2D LHPs, [R-1-(4-bromophenyl)ethylaminium]2PbI4 (R-[BPEA]2PbI4) and [S-1-(4-bromophenyl)ethylaminium]2PbI4 (S-[BPEA]2PbI4). Our results show that these chiral perovskites are direct bandgap semiconductors and exhibit CPPL centered at ∼513 nm with a maximum degree of polarization of up to 11.0% at room temperature. In addition, the unique configurational arrangement of the chiral spacers is found to be able to reduce the interlayer π-π interactions and consequently result in strong electron-phonon coupling. Furthermore, the intrinsic chirality of both R-[BPEA]2PbI4 and S-[BPEA]2PbI4 enables them to be piezoelectric active, and their composite films can be applied to generate voltages and currents up to ∼0.6 V and ∼1.5 μA under periodic impacting with a strength of 2 N, respectively. This work not only reports a high degree of CPPL but also demonstrates piezoelectric energy harvesting behavior for realizing multifunctionalities in chiral 2D LHPs.

31 citations


Journal ArticleDOI
TL;DR: In this paper , a pair of chiral green emitters denoted as (R )- BN-MeIAc and (S ) -BN-MEIAc is designed.
Abstract: Highly efficient circularly polarized luminescence (CPL) emitters with narrowband emission remain a formidable challenge for circularly polarized OLEDs (CP-OLEDs). Here, a promising strategy for developing chiral emitters concurrently featuring multi-resonance TADF (MR-TADF) and circularly polarized electroluminescence (CPEL) is demonstrated by the integration of molecular rigidity, central chirality and MR effect. A pair of chiral green emitters denoted as ( R )- BN-MeIAc and ( S )- BN-MeIAc is designed. Benefited by the rigid and quasi-planar MR-framework, the enantiomers not only display mirror-image CPL spectra, but also exhibit TADF properties with high photoluminescence quantum yield of 96%, narrow FWHM of 30 nm, and high horizontal dipole orientation of 90% in doped film. Consequently, the enantiomer-based CP-OLEDs achieved excellent external quantum efficiencies of 37.2% with very low efficiency roll-off, representing the highest device efficiency of all the reported CP-OLEDs.

31 citations


Journal ArticleDOI
02 Feb 2022-ACS Nano
TL;DR: In this article , a CPL detector based on quasi two-dimensional (quasi-2D) chiral perovskite films is presented, which exhibits both a high dissymmetry factor of 0.15 and a high responsivity of 15.7 A W −1.
Abstract: Circularly polarized light (CPL) has considerable technological potential, from quantum computing to bioimaging. To maximize the opportunity, high performance photodetectors that can directly distinguish left-handed and right-handed circularly polarized light are needed. Hybrid organic–inorganic perovskites containing chiral organic ligands are an emerging candidate for the active material in CPL photodetecting devices, but current studies suggest there to be a trade-off between the ability to differentially absorb CPL and photocurrent responsivity in chiral perovskites devices. Here, we report a CPL detector based on quasi two-dimensional (quasi-2D) chiral perovskite films. We find it is possible to generate materials where the circular dichroism (CD) is comparable in both 2D and quasi-2D films, while the responsivity of the photodetector improves for the latter. Given this, we are able to showcase a CPL photodetector that exhibits both a high dissymmetry factor of 0.15 and a high responsivity of 15.7 A W–1. We believe our data further advocates the potential of chiral perovskites in CPL-dependent photonic technologies.

Journal ArticleDOI
TL;DR: In this article , a multifunctional coding metasurface (MCMS) has been proposed to realize dual-circularly polarized beams and beam focusing with transmission and reflection, where the phase distribution of the circularly polarized four-beam is determined according to the convolution theorem of patterns and the phase compensation principle.
Abstract: In this paper, a multifunctional coding metasurface (MCMS) has been proposed to realize dual-circularly polarized beams and beam focusing with transmission and reflection. The phase of transmissive wave is controlled by rotating the elements, and the corresponding element, which consists of two quadrate voids etched on a single layer substrate, is designed for the metasurface with Pancharatnam-Berry (PB) phase. The phase distribution of the circularly polarized four-beam is determined according to the convolution theorem of patterns and the phase compensation principle. In order to validate the proposed metasurface, the multifunctional meta-device is fabricated and measured to illustrate the four-beam with left circular polarization in transmissive space and the right circularly polarized four-beam in reflective space by MCMS with x-polarized incidence. The experimental results heavily agree with the simulated data. The MCMS has potential applications in wireless communications due to its low profile, compact, and lightweight features.

Journal ArticleDOI
TL;DR: In this paper , the authors demonstrate that the use of inorganic nanometric chiral templates for the controlled assembly of Au and TiO2 nanoparticles leads to the formation of plasmon-based photocatalysts with polarization-dependent reactivity.
Abstract: Mastering the manipulation of chirality at the nanoscale has long been a priority for chemists, physicists, and materials scientists, given its importance in the biochemical processes of the natural world and in the development of novel technologies. In this vein, the formation of novel metamaterials and sensing platforms resulting from the synergic combination of chirality and plasmonics has opened new avenues in nano-optics. Recently, the implementation of chiral plasmonic nanostructures in photocatalysis has been proposed theoretically as a means to drive polarization-dependent photochemistry. In the present work, we demonstrate that the use of inorganic nanometric chiral templates for the controlled assembly of Au and TiO2 nanoparticles leads to the formation of plasmon-based photocatalysts with polarization-dependent reactivity. The formation of plasmonic assemblies with chiroptical activities induces the asymmetric formation of hot electrons and holes generated via electromagnetic excitation, opening the door to novel photocatalytic and optoelectronic features. More precisely, we demonstrate that the reaction yield can be improved when the helicity of the circularly polarized light used to activate the plasmonic component matches the handedness of the chiral substrate. Our approach may enable new applications in the fields of chirality and photocatalysis, particularly toward plasmon-induced chiral photochemistry.

Journal ArticleDOI
TL;DR: The geometric phase of light has been demonstrated in various platforms of the linear optical regime, raising interest both for fundamental science as well as applications, such as flat optical elements as discussed by the authors.
Abstract: The geometric phase of light has been demonstrated in various platforms of the linear optical regime, raising interest both for fundamental science as well as applications, such as flat optical elements. Recently, the concept of geometric phases has been extended to nonlinear optics, following advances in engineering both bulk nonlinear photonic crystals and nonlinear metasurfaces. These new technologies offer a great promise of applications for nonlinear manipulation of light. In this review, we cover the recent theoretical and experimental advances in the field of geometric phases accompanying nonlinear frequency conversion. We first consider the case of bulk nonlinear photonic crystals, in which the interaction between propagating waves is quasi-phase-matched, with an engineerable geometric phase accumulated by the light. Nonlinear photonic crystals can offer efficient and robust frequency conversion in both the linearized and fully-nonlinear regimes of interaction, and allow for several applications including adiabatic mode conversion, electromagnetic nonreciprocity and novel topological effects for light. We then cover the rapidly-growing field of nonlinear Pancharatnam-Berry metasurfaces, which allow the simultaneous nonlinear generation and shaping of light by using ultrathin optical elements with subwavelength phase and amplitude resolution. We discuss the macroscopic selection rules that depend on the rotational symmetry of the constituent meta-atoms, the order of the harmonic generations, and the change in circular polarization. Continuous geometric phase gradients allow the steering of light beams and shaping of their spatial modes. More complex designs perform nonlinear imaging and multiplex nonlinear holograms, where the functionality is varied according to the generated harmonic order and polarization. Recent advancements in the fabrication of three dimensional nonlinear photonic crystals, as well as the pursuit of quantum light sources based on nonlinear metasurfaces, offer exciting new possibilities for novel nonlinear optical applications based on geometric phases.

Journal ArticleDOI
TL;DR: In this paper , a high-efficiency full-space metasurface (MS) is demonstrated numerically, which can independently manipulate the transmitted linear polarization (LP) and the reflected circular polarization (CP) wavefront based on the transmission and geometric phase at terahertz (THz) range.


Journal ArticleDOI
TL;DR: The BBC has confirmed it will not be broadcasting live coverage of the Rugby World Cup in Russia this summer because of concerns over the level of public support for the tournament and the security situation.
Abstract: XXXXXXXXXXXXX This article is protected by copyright. All rights reserved.

Journal ArticleDOI
TL;DR: In this paper , the authors summarize the recent progress on the chiral materials developed for CPL detection and provide perspectives on strategies to improve the dissymmetry factors, which is central to many advanced sensing technologies.
Abstract: Detecting circularly polarized light is central to many advanced sensing technologies. We summarize the recent progress on the chiral materials developed for CPL detection and provide perspectives on strategies to improve the dissymmetry factors.

Journal ArticleDOI
TL;DR: In this paper , the authors reported the experimental realization of true/intrinsic chiral response with resonant metasurfaces in which the engineered slant geometry breaks both in-plane and out-of-plane symmetries.
Abstract: Photons with spin angular momentum possess intrinsic chirality, which underpins many phenomena including nonlinear optics1, quantum optics2, topological photonics3 and chiroptics4. Intrinsic chirality is weak in natural materials, and recent theoretical proposals5-7 aimed to enlarge circular dichroism by resonant metasurfaces supporting bound states in the continuum that enhance substantially chiral light-matter interactions. Those insightful works resort to three-dimensional sophisticated geometries, which are too challenging to be realized for optical frequencies8. Therefore, most of the experimental attempts9-11 showing strong circular dichroism rely on false/extrinsic chirality by using either oblique incidence9,10 or structural anisotropy11. Here we report on the experimental realization of true/intrinsic chiral response with resonant metasurfaces in which the engineered slant geometry breaks both in-plane and out-of-plane symmetries. Our result marks, to our knowledge, the first observation of intrinsic chiral bound states in the continuum with near-unity circular dichroism of 0.93 and a high quality factor exceeding 2,663 for visible frequencies. Our chiral metasurfaces may lead to a plethora of applications in chiral light sources and detectors, chiral sensing, valleytronics and asymmetric photocatalysis.

Journal ArticleDOI
TL;DR: In this paper , a scheme of spin-controlling multi-beam by transmissive coding metasurface is proposed for dual-circular polarization simultaneously, and the phase distribution is designed based on the convolution theorem.
Abstract: The Pancharatnam-Berry (PB) phase can be used to control the phase of circularly polarized electromagnetic waves. However, there are few studies on the modulation of dual-circularly polarized multi-beam using the transmissive coding metasurface. A scheme of spin-controlling multi-beam by transmissive coding metasurface is proposed for dual-circular polarization simultaneously. The transmissive coding metasurface (TCMS) can transmit linearly polarized incidence into multi-beam with orthogonally circular polarization. The phase distribution is designed based the convolution theorem, and the elements of metasurface conforming to the PB phase are arranged according to the phase distribution. In order to compensate the emitting spherical waves into plane waves and realize the transmissive waves with dual-circular polarization, an interesting scheme of elements in different regions with different rotating phase are presented based on the principle of phase compensation. TCMS can transmit linearly polarized waves into two left-hand circularly polarized (LHCP) beams and two right-hand circularly polarized (RHCP) beams. The prototype of TCMS is fabricated and measured, and the experimental results agree well with the simulated data. The transmissive metasurface has potential application in holograms and satellite communication.

Journal ArticleDOI
TL;DR: In this paper , a 90° twisted quarter sectored circularly polarized and high gain dielectric resonator antenna (DRA) operating within the 5.8 GHz Wi-Fi band was investigated.
Abstract: Radio frequency (RF) energy harvesting is the most adopted technique for replacing conventional batteries. However, the available RF energy in the surrounding atmosphere is low and unstable, so the antenna with high gain and polarization-insensitive characteristics is desired to collect a massive amount of power from the low-density environment. A 90° twisted quarter sectored circularly polarized and high gain dielectric resonator antenna (DRA) operating within the 5.8 GHz Wi-Fi band, is investigated first time of its kind in this letter. A circular-shaped aperture coupled feeding approach is investigated for energizing the proposed antenna. A metallic strip is placed on the right face of the optimized DRA for creating circular polarization characteristics. The optimized antenna (0.67 λ×0.67 λ×0.029 λ) offers a gain value of 7.02 dBc at 5.8 GHz frequency. A shunt-diode rectifier circuit is implemented for rectification purposes. The power conversion efficiency achieved at the operating frequency is 72.5% for an input power level of 5.75 dBm.

Journal ArticleDOI
TL;DR: In this paper , the asymmetric hydrogen-bonding interaction between chiral molecular spacers and the inorganic framework plays a key role in promoting the chiroptical activity of chiral perovskites.
Abstract: Chiral perovskites are being extensively studied as a promising candidate for spintronic- and polarization-based optoelectronic devices due to their interesting spin-polarization properties. However, the origin of chiroptical activity in chiral perovskites is still unknown, as the chirality transfer mechanism has been rarely explored. Here, through the nano-confined growth of chiral perovskites (MBA2PbI4(1-x)Br4x), we verified that the asymmetric hydrogen-bonding interaction between chiral molecular spacers and the inorganic framework plays a key role in promoting the chiroptical activity of chiral perovskites. Based on this understanding, we observed remarkable asymmetry behavior (absorption dissymmetry of 2.0 × 10-3 and anisotropy factor of photoluminescence of 6.4 × 10-2 for left- and right-handed circularly polarized light) in nanoconfined chiral perovskites even at room temperature. Our findings suggest that electronic interactions between building blocks should be considered when interpreting the chirality transfer phenomena and designing hybrid materials for future spintronic and polarization-based devices.

Journal ArticleDOI
TL;DR: In this article , the asymmetric hydrogen-bonding interaction between chiral molecular spacers and the inorganic framework plays a key role in promoting the chiroptical activity of chiral perovskites.
Abstract: Chiral perovskites are being extensively studied as a promising candidate for spintronic- and polarization-based optoelectronic devices due to their interesting spin-polarization properties. However, the origin of chiroptical activity in chiral perovskites is still unknown, as the chirality transfer mechanism has been rarely explored. Here, through the nano-confined growth of chiral perovskites (MBA2PbI4(1-x)Br4x), we verified that the asymmetric hydrogen-bonding interaction between chiral molecular spacers and the inorganic framework plays a key role in promoting the chiroptical activity of chiral perovskites. Based on this understanding, we observed remarkable asymmetry behavior (absorption dissymmetry of 2.0 × 10-3 and anisotropy factor of photoluminescence of 6.4 × 10-2 for left- and right-handed circularly polarized light) in nanoconfined chiral perovskites even at room temperature. Our findings suggest that electronic interactions between building blocks should be considered when interpreting the chirality transfer phenomena and designing hybrid materials for future spintronic and polarization-based devices.

Journal ArticleDOI
TL;DR: In this paper , a broadband reflective dual-functional polarization convertor based on all-metal anisotropic metasurface was proposed and investigated numerically in visible region, which can convert the incident linear polarization light into its orthogonal counterpart or circular polarization light by adjusting the geometric parameter of the ellipse nanostructure.
Abstract: In this paper, a broadband reflective dual-functional polarization convertor based on all-metal anisotropic metasurface was proposed and investigated numerically in visible region. The unit-cell of the all-metal anisotropic metasurface based polarization convertor is composed of the Au ellipse nanostructure adhered on an Au substrate. The proposed anisotropic metasurface can convert the incident linear polarization light into its orthogonal counterpart or circular polarization light by adjusting the geometric parameter of the ellipse nanostructure. When the all-metal anisotropic metasurface functioned as a linear-to-linear polarization convertor (LLPC), the conversion efficiency is over 90% operating from 356.5 THz to 536.5 THz. While the metasurface served as a linear-to-circular polarization convertor (LCPC), the absolute value of polarization extinction ratio (PER) is greater than 10 dB from 336.5 THz to 544.5 THz. The simulated electric field distributions on the unit-cell indicate that the higher polarization converion efficiency is mianly originated from the geometry anistropy and excitations of fundamental and higher-order dipolar plasmon resonance. Thus, our design can be found potential applications in many areas, such as remote nano-sensors, nano-antennas, and radiometers in visible region.

Journal ArticleDOI
TL;DR: In this article , a dual-band and dual-linearly polarized patch antenna is adopted as the feed source to reduce the profile of the whole antenna, which has the advantages of compact planar structure, low cost, high gain, and easy integration, which presents great application potential in two-way satellite communication systems with limited volume and space.
Abstract: This communication presents a low-profile, compact, high gain dual-band and dual-circularly polarized (CP) folded transmitarray antenna (FTA) with independent beam control at Ku-band. The element with independent phase control capability in two bands is designed to achieve the functionality of linear polarization to different circular polarization conversion. To reduce the profile of the whole FTA, a dual-band and dual-linearly polarized patch antenna is adopted as the feed source. By controlling the phase distribution and circular polarization of the transmitarray (TA) according to the phase compensation principle, the proposed antenna can radiate left-hand CP (LCP) waves and right-hand CP (RCP) waves at 12 and 15 GHz, respectively. On the basis, three typical FTA prototypes with different beam directions are simulated to validate the capability of independent beam control. Two of the prototypes are fabricated and measured, and the results are shown in reasonable agreement with the simulation. The proposed antenna not only reduces the profile by 2/3 compared to the traditional TA antenna, but also has the advantages of compact planar structure, low cost, high gain, and easy integration, which presents great application potential in two-way satellite communication systems with limited volume and space.

Journal ArticleDOI
TL;DR: In this paper , an explicit analytic formula for the spin Hall shift is derived under arbitrarily polarized incidence, and it is shown that the spin-hall shift can be enhanced at any incident angle by using polarization degree of freedom and independent of the Fresnel coefficients of an interface under circularly polarized light.
Abstract: Abstract The spin Hall effect of light (SHEL) is the microscopic spin-dependent splitting of light at an optical interface. Whereas the spin Hall shift under linearly polarized light is well-formulated, studies on the SHEL under elliptically or circularly polarized light have primarily relied on numerical computation. In this work, an explicit analytic formula for the spin Hall shift is derived under arbitrarily polarized incidence. Furthermore, from this explicit expression, we demonstrate that the spin Hall shift can be enhanced at any incident angle by using polarization degree of freedom and is independent of the Fresnel coefficients of an interface under circularly polarized light. The analytic formula will help us understand the SHEL under general polarization intuitively and realize unprecedented modulation of the SHEL.

Journal ArticleDOI
TL;DR: A dual-band dual-rotational-direction reflective linear-to-circular polarization converter based on metasurface is designed, fabricated, and measured in this paper, where an open ring creates two resonances, and the square patch is used to improve the axial ratio (AR).
Abstract: A dual-band dual-rotational-direction reflective linear-to-circular polarization converter based on metasurface is designed, fabricated, and measured. The unit cell consists of an open ring and a square patch. The open ring creates two resonances, and the square patch is used to improve the axial ratio (AR). It is shown that this design can be working at two frequency bands, i.e., 29.0–41.5 GHz and 52.5–61.5 GHz. Interestingly, it is found that the linearly polarized wave in $x(y)$ -direction can be converted into right(left)-handed circularly polarized wave at the former band, and into left(right)-handed circularly polarized wave at the later band. Compared to other designs in the literature, this design demonstrates 45° angular stability for 3 dB AR over two operational bands. In addition, this design is realized on a single substrate, making it easier to be fabricated. Furthermore, the insertion loss can be as low as 0.5 dB, showing a very low-loss property. Lastly, the unit cell is less than 0.2 wavelength at the lower frequency band. The measured results show good agreement with simulation. Potential applications can be envisaged in dual-band and dual-polarization communication.

Journal ArticleDOI
TL;DR: In this article , a low-cost wearable sensor may be evaluated by printing the microstrip antenna with the sensor feed network and the active devices on the same substrate, and the electrical performance of the novel sensors and antennas on and near the user body were evaluated by employing electromagnetic software.
Abstract: Novel circular polarized sensors and antennas for biomedical systems, energy harvesting, Internet of Things (IoT), and 5G devices are presented in this article. The major challenge in development of healthcare, IoT, 5G and communication systems is the evaluation of circular polarized active and passive wearable antennas. Moreover, a low-cost wearable sensor may be evaluated by printing the microstrip antenna with the sensor feed network and the active devices on the same substrate. Design considerations, comparison between simulation and measured results of compact circular polarized efficient sensors for wireless, 5G, energy harvesting, IoT, and medical systems are highlighted in this article. The electrical performance of the novel sensors and antennas on and near the user body were evaluated by employing electromagnetic software. Efficient passive and active metamaterial circular polarized antennas and sensors were developed to improve the system electrical performance. The wearable compact circular polarized passive and active sensors are efficient, flexible, and low-cost. The frequency range of the resonators, without Circular Split-Ring Resonators CSRRs, is higher by 4% to 10% than the resonators with CSRRs. The gain of the circular polarized antennas without CSRRs is lower by 2 dB to 3 dB than the resonators with CSRRs. The gain of the new passive antennas with CSRRs is around 7 dBi to 8.4 dBi. The bandwidth of the new circular polarized antennas with CSRRs is around 10% to 20%. The sensors VSWR is better than 3:1. The passive and active efficient metamaterials antennas improve the system performance.

Journal ArticleDOI
TL;DR: In this paper , the first hot exciton fluorescent material based on benzo[c][1,2,5]thiadiazole and chiral binaphthol enabling circularly polarized luminescence (CPL) through a chiral perturbation strategy was described.
Abstract: This work describes the first hot exciton fluorescent material based on benzo[c][1,2,5]thiadiazole and chiral binaphthol enabling circularly polarized luminescence (CPL) through a chiral perturbation strategy. The new molecular architecture displays CPL, hybridized local and charge transfer (HLCT) properties concurrently. Utilizing it as the emitter, circularly polarized organic light‐emitting diodes (CP‐OLEDs) achieve an external quantum efficiency (EQE) of 7.2% with a good exciton utilization (36%) and a moderate circularly polarized electroluminescence (CPEL) dissymmetry factor (gEL, 2.1 × 10−3). In addition, the CP‐HLCT molecule is sensitized by a thermally activated delayed fluorescence material, significantly ameliorating the efficiency of HLCT fluorescent CP‐OLEDs. Excellent performances of twofold maximum EQE (EQEmax) of 15.3% and 82% exciton utilization are obtained in the sensitized device, regarding an extremely low‐efficiency roll‐off of 2.6% at 1000 cd m−2 as well as CPEL with a gEL value of 2.0 × 10−3.

Journal ArticleDOI
01 Jul 2022
TL;DR: In this article , a high-gain bidirectional radiative circular polarization (CP) antenna loaded with a dual-mode focusing metasurface (MS) is proposed, which can independently tailor the focusing effect of transmitted and reflected CP waves at 8.15 GHz and 14.8 GHz, respectively.
Abstract: A high-gain bidirectional radiative circular polarization (CP) antenna loaded with a dual-mode focusing metasurface (MS) is proposed. The original microstrip patch antenna consists of two coaxially fed tangential patches with different sizes, enabling CP radiation at 8.15 GHz and 14.8 GHz with the gain of 5.4 dBic and 6.2 dBic, respectively. The unit-cell of the focusing MS is composed of two metallic layers separated by a dielectric substrate based on geometric phase principle, which can independently tailor the focusing effect of transmitted and reflected CP waves at 8.15 GHz and 14.8 GHz, respectively. Then, the high-gain bidirectional radiation antenna can be formed by combining the original CP microstrip antenna and focusing MS. The final designed antenna can achieve a CP radiation converge characteristic in transmission at 8.15 GHz with a peak gain of 15.9 dBic, and at 14.8 GHz with a peak gain of 19.4 dBic in refection, respectively. In order to verify the feasibility of the proposed design, the bidirectional radiative CP antenna with/without focusing MS were fabricated and measured, and the results are consistent basically with the simulated ones. The proposed bidirectional focusing MS antenna could provide an effective solution for dual-mode radiation and high-rate information transmission of the communication system.