- 标题
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- 实验方案
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Local Optical Chirality Induced by Near-Field Mode Interference in Achiral Plasmonic Metamolecules
摘要： When circularly polarized light interacts with a nanostructure, the optical response depends on the geometry of the structure. If the nanostructure is chiral (i.e. it cannot be superimposed on its mirror image) then its optical response, both in near-field and far-field, depends on the handedness of the incident light. In contrast, achiral structures exhibit identical far-field responses for left- and right-circular polarization. Here, we show that a perfectly achiral nanostructure, a plasmonic metamolecule with trigonal D3h symmetry, exhibits a near-field response that is sensitive to the handedness of light. This effect stems from the near-field interference between the different plasmonic modes sustained by the plasmonic metamolecule under circularly polarized light excitation. The local chirality in a plasmonic trimer is then experimentally evidenced with nanoscale resolution using a molecular probe. Our experiments demonstrate that the optical near-field chirality can be imprinted into the photosensitive polymer, turning the optical chirality into a geometrical chirality that can be imaged using atomic force microscopy. These results are of interest for the field of polarization-sensitive photochemistry.
关键词： circular polarization,plasmonic metamolecules,Chirality,chiral plasmonics,photopolymers
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Generation of Broad-Band Circularly Polarised Supercontinuum in Chiral Photonic Crystal Fibre
摘要： Supercontinuum (SC) generation in solid-core photonic crystal fibres (PCFs) is well established and has diverse applications in science and technology [1,2]. In a conventional SC, the polarization state is not maintained over the whole spectrum due to cross-phase modulation and may in addition vary with power. Recently, it has been reported that continuously twisted PCFs exhibit circular birefringence [3,4]. Here we report the first experimental demonstration of a twisted PCF that robustly maintains circular polarization state across the whole spectrum, independent of power.
关键词： Supercontinuum generation,chiral light-matter interactions,photonic crystal fibres,circular polarization
更新于2025-09-12 10:27:22
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12.1: <i>Invited Paper:</i> Polarization control and optical efficiency improvement of light emitted from OLED using liquid crystalline luminophores
摘要： Highly circularly polarized (CP) light is generated by using a twisted conjugated polymer structure with a small amount of chiral molecules as the light emitting layer of the OLED. It is confirmed that the luminous efficiency is increased by 60% compared to the conventional OLED structure.
关键词： organic light emitting diodes,conjugated polymer,polarized emission,chiral dopant,Circular polarization
更新于2025-09-11 14:15:04
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Design of a Compact 3D Metal Printed Ka-band Waveguide Polarizer
摘要： This letter presents design, development and characterization of compact wide band 3D printed circular waveguide based polarizer operating in Ka-band (28-34 GHz). The polarizer structure is investigated using fundamental and higher order modes and based on which a simplified equivalent structure is derived giving physical insight into its mechanism of operation. The design consists of a pair of radially opposite grooves inside a circular waveguide and excited using a coaxial probe which makes the design simple and highly compact as compared to other conventional circular polarizers. The design is compared with other existing waveguide based polarizers in terms of electrical and physical parameters. Fabrication is done using high resolution direct metal aluminum 3D metal printing. The measured axial ratio is better than 3 dB over the frequency band. The design simplicity makes it attractive for application in millimeter wave frequencies and beyond.
关键词： polarizers,septum,waveguide,ridge waveguides,groove,Circular polarization
更新于2025-09-11 14:15:04
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Broadband Linear-to-Circular Polarization Conversion Enabled by Birefringent Off-Resonance Reflective Metasurfaces
摘要： Due to the scarcity of circular polarization light sources, linear-to-circular polarization conversion is required to generate circularly polarized light for a variety of applications. Despite significant past efforts, broadband linear-to-circular polarization conversion remains elusive particularly in the terahertz and midinfrared frequency ranges. Here we propose a novel mechanism based on coupled mode theory, and experimentally demonstrate at terahertz frequencies that highly efficient (power conversion efficiency approaching unity) and ultrabroadband (fractional bandwidth up to 80%) linear-to-circular polarization conversion can be accomplished by the judicious design of birefringent metasurfaces. The underlying mechanism operates in the frequency range between well separated resonances, and relies upon the phase response of these resonances away from the resonant frequencies, as well as the balance of the resonant and nonresonant channels. This mechanism is applicable for any operating frequencies from microwave to visible. The present Letter potentially opens a wide range of opportunities in wireless communications, spectroscopy, and emergent quantum materials research where circularly polarized light is desired.
关键词： linear-to-circular polarization conversion,midinfrared,birefringent metasurfaces,terahertz,broadband
更新于2025-09-11 14:15:04
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[IEEE 2018 3rd International Symposium on Instrumentation Systems, Circuits and Transducers (INSCIT) - Bento Gon?alves, Brazil (2018.8.27-2018.8.31)] 2018 3rd International Symposium on Instrumentation Systems, Circuits and Transducers (INSCIT) - Low-cost circular-polarizared patch antenna for RFID applications
摘要： In this paper, a low-cost patch antenna with circular polarization using a FR4 substrate is proposed. The antenna was developed to be used in US standard UHF RFID application, with better impedance matching at 915MHz. The design was concepted and optimized through simulations using the ANSYS HFSS software. The simulation results presented an absolute gain of 5.76dB, an axial ratio of 1.87dB and the return loss (S11) of 48dB at 915MHz. The antenna was manufactured and measurements of the return loss using the Keysight Vector Network Analyzer were made to compare with the simulation results. Furthermore, it was compared to a commercial antenna by reading a commercial tag using a RFID reader in order to validate the proposed antenna application.
关键词： optimization,design,circular polarization,UHF,antenna,RFID
更新于2025-09-11 14:15:04
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[IEEE 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Chengdu, China (2018.3.26-2018.3.28)] 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Design of a Low Profile Omnidirectional Circular Polarized Reconfigurable Antenna for Beidou Application
摘要： A low profile omnidirectional circular polarized reconfigurable antenna for Beidou application is proposed in this paper. This antenna is based on the first-order resonance mode of epsilon negative transmission line. To form a circularly polarized wave in the far field, the vertical and horizontal polarization is generated by a parallel circular cavity and three dual arc arms, respectively. Only 6 PIN diodes are needed to alter the left-handed circularly polarized (LHCP) or right- handed circularly polarized (RHCP) omnidirectional radiation state. Three-dimensional electromagnetic simulation software Ansoft HFSS and RF circuit simulation software Agilent ADS are used for co-simulation and optimization. It is shown that the proposed antenna can meet the Beidou navigation BDS-1 S band requirement well whether at the left or right circularly polarized state. The omnidirectional average axial ratio at two states are 1.24 dB and 1.25 dB with 16.7 % and 19.8 % 3 dB axial ratio bandwidth, respectively. The thickness of antenna is only 2 mm (0.016 (cid:540)0) and simply processed without a dual feeding structure and 90 phase shifter.
关键词： circular polarization reconfigurable,PIN diode,omnidirectional antenna,low profile
更新于2025-09-10 09:29:36
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[Lecture Notes in Electrical Engineering] Microelectronics, Electromagnetics and Telecommunications Volume 521 (Proceedings of the Fourth ICMEET 2018) || Wideband Circular Polarized Binomial Antenna Array for L-Band Radar
摘要： This paper presents a compact binomial rectangular patch antenna array with wide bandwidth and circular polarization for the L-band radar application operating at the frequency of 1.35 GHz. A 16-element planar antenna array is designed with independent coaxial feed to each element which helps in reduction of negative effects of complex feed network on antenna performance. The patch elements are truncated diagonally which is useful in producing circular polarization. There is an air cavity in between the ground plane and substrate which helps in improving the gain of the antenna and the cumulative effect of the truncated patches and the air cavity will increase the bandwidth of the antenna. The inter-element spacing in the antenna array is considered as half of the free space wavelength. The antenna elements are fed with nonuniform amplitudes to reduce the side lobe levels which are a major problem in radar applications for this Pascal triangle coef?cient are considered for feeding the antenna elements.
关键词： Binomial array,Side lobe level,Wideband,Circular polarization
更新于2025-09-10 09:29:36
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Circularly polarized implantable antenna characterization for retinal prosthesis systems
摘要： We describe a miniaturized antenna design for retinal prosthesis applications that enhances data transfer between the implant and external camera. The circularly polarized and conformal 2.4{2.48 GHz microstrip patch antenna was simulated inside the vitreous humor and is intended for biomedical applications. Modi(cid:12)ed Hilbert and serpentine geometries were used for the proposed implant antenna design. Capacitive radiator loading o?ered miniaturized dimensions of 5.8 (cid:2) 6.5 (cid:2) 2 mm 3 (width (cid:2) height (cid:2) thickness mm 3) . A truncated design enhanced the intrinsic circular polarization characteristics to > 3 dB axial ratio. Polydimethylsiloxane substrate and superstrate materials were used to achieve an S 11 value below {15 dB across the frequency range with biocompatible characteristics. The simulated peak gains for left-hand circular polarization and right-hand circular polarization at 2.45 GHz were {50 dBi and {60 dBi, respectively. These relatively small values were due to the high conductivity of the vitreous humor ( (cid:27) = 1.53 S/m), which imposed signi(cid:12)cant losses. Overall, the proposed antenna had an omnidirectional radiation pattern and + 8.45 dBm input to meet the speci(cid:12)c absorption rate regulation limit.
关键词： miniaturized,circular polarization,retinal prosthesis systems,Implant antenna
更新于2025-09-10 09:29:36
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[IEEE 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Espoo, Finland (2018.8.27-2018.9.1)] 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Self-complementary tessellations as universal design approach for LP-to-CP transforming frequency selective surfaces
摘要： Recently self-complementary frequency-selective surfaces (FSSs) have been shown capable of linear-to-circular polarization transformation. In this work we numerically and experimentally prove generality of this approach showing that similar self-complementary tessellations can be used as FSS patterns in both the microwave and the sub-millimeter wave ranges. Moreover, we simulated two Escher’s tessellations as patterns of microwave FSSs to further demonstrate the polarization transform function of arbitrary self-complementary FSSs.
关键词： linear-to-circular polarization transformation,self-complementary tessellations,microwave,sub-millimeter wave,frequency-selective surfaces
更新于2025-09-10 09:29:36