- 标题
- 摘要
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- 实验方案
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Anisotropic infrared light emission from quasi-one-dimensional layered TiS<sub>3</sub>
摘要： Atomically thin semiconductors hold great potential for nanoscale photonic and optoelectronic devices because of their strong light absorption and emission. Despite progress, their application in integrated photonics is hindered particularly by a lack of stable layered semiconductors emitting in the infrared part of the electromagnetic spectrum. Here we show that titanium trisulfide (TiS3), a layered van der Waals material consisting of quasi-one-dimensional chains, emits near infrared light centered around 0.91 eV (1360 nm). Its photoluminescence exhibits linear polarization anisotropy and an emission lifetime of 210 ps. At low temperature, we distinguish two spectral contributions with opposite linear polarizations attributed to excitons and defects. Moreover, the dependence on excitation power and temperature suggests that free and bound excitons dominate the excitonic emission at high and low temperatures, respectively. Our results demonstrate the promising properties of TiS3 as a stable semiconductor for optoelectronic and nanophotonic devices operating at telecommunication wavelengths.
关键词： infrared luminescence,transition metal trichalcogenides,titanium trisulfide,linear polarization anisotropy,layered semiconductors
更新于2025-11-14 14:32:36
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60-GHz 2-D Scanning Multibeam Cavity Backed Patch Array fed by Compact SIW Beam-Forming Network for 5G Applications
摘要： This paper presents a 2x2 multibeam array employing a novel wideband linearly polarized cavity-backed patch antenna for fifth generation (5G) wireless communication technology. The antenna array comprises four layers stacked on top of one another. The proposed antenna element is composed of three substrate layers and excited using a substrate integrated waveguide (SIW) aperture-coupled feed. The antenna element exhibits -10-dB impedance bandwidth of 36.2% from 53 to 76.4 GHz with very flat gain and excellent radiation characteristics. A prototype is fabricated and tested. The compact 2-D scanning multibeam 2x2 antenna array is demonstrated at 60-GHz, where the proposed antenna element is utilized as a radiating element. By employing a novel compact beam forming network (BFN) in the design, the proposed array achieves a size reduction of better than 28% compared to an array fed with conventional BFN, without degradation in the array performance. A wide bandwidth larger than 27 % for |S11|<-10 dB and a peak gain of 12.4 dBi is achieved. The array shows a good symmetrical radiation pattern in the two perpendicular planes. Verified by prototype measurements, the proposed antenna element and multibeam array with features of a compact structure, low cost, wide bandwidth and superior radiation performance, would be practically attractive for 5G applications.
关键词： fifth generation (5G),linear polarization,60 GHz,SIW,beam-forming network,multibeam antenna
更新于2025-09-23 15:22:29
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45?° Linearly Polarized and Circularly Polarized High-Scanning-Rate Leaky-Wave Antennas Based on Slotted Substrate Integrated Waveguide
摘要： A class of 45? linearly polarized and circular polarized high scanning rate leaky wave antennas are proposed in this paper, which is based on slow-wave substrate integrated waveguide structure. High scanning rate leaky wave antennas have recently become attractive for imaging applications and automotive radar. These applications also require a continuous scanning range without an open stopband, as seen at broadside for ordinary leaky wave antennas. Furthermore, both 45? linearly polarization and circularly polarization are required in practical applications. In this paper, we propose an all-in-one leaky wave antenna design, which features high scanning rate, continuous scanning capability across the broadside, 45? linear polarization or circularly polarization, single-layer configuration, and single-side radiation. Two design examples are provided to illustrate the proposed principle. Both simulation and experimental validation are given.
关键词： open stopband,Leaky wave antenna,substrate integrated waveguide,circular polarization,scanning rate,linear polarization
更新于2025-09-23 15:21:01
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Broadband high-efficiency cross-polarization conversion and multi-functional wavefront manipulation based on chiral structure metasurface for terahertz wave
摘要： In this paper, a broadband and high-efficient tri-layered chiral structure metasurface (CSM) for linear polarization conversion and multi-functional wavefront manipulation was proposed and investigated numerically in terahertz region. The unit-cell of the proposed CSM consist of two orthogonal metal wires sandwiched with square split-ring resonator (SRR) structure, which can manipulate the polarization and wavefront of the transmitted wave simultaneously. Based on the Fabry-Perot-like cavity-enhanced effect of proposed CSM, broadband and high-efficiency cross-polarization conversion can be achieved. Numerical simulation results indicate that the cross-polarization transmission coefficient is higher than 0.9 from 0.4 THz to 1.0 THz, with a fractional bandwidth of 85.7%. The proposed CSM can achieve complete 2π phase coverage by adjusting the geometric parameters of the unit-cell structure. As a proof of multi-functional wavefront manipulation, anomalous refraction with a wide angle, two kinds of focusing metalenses and vortex beam generation are investigated to verify the multi-functional wavefront manipulation performance of the proposed CSM. Our work provides an effective method of enhancing the performance of transmission-type metasurface and the proposed devices show endless potential in wavefront control and communication applications in terahertz region.
关键词： chiral structure metasurface,linear polarization conversion,terahertz,wavefront manipulation
更新于2025-09-23 15:19:57
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[IEEE GLOBECOM 2019 - 2019 IEEE Global Communications Conference - Waikoloa, HI, USA (2019.12.9-2019.12.13)] 2019 IEEE Global Communications Conference (GLOBECOM) - Mutual Information and Noise Distributions of Molecular Signals Using Laser Induced Fluorescence
摘要： In this communication, a recon?gurable feeding network is proposed for the design of a quad-polarization-agile antenna. By switching the PIN diodes, the four transmission modes with selected phase differences can be electrically tuned at two output ports. For each mode, the measured insertion loss of the feeding network is less than 0.8 dB at the operating frequency. Because of its compact size, the proposed feeding network can be further integrated with a dual-polarized aperture-coupled antenna, which can exhibit two orthogonal linear polarizations and two orthogonal circular polarizations. Measured results of the polarization-agile antenna are shown in detail, which verify its performance.
关键词： recon?gurable antenna,circular and linear polarization,recon?gurable feeding network,Aperture-coupled patch antenna,polarization-agile
更新于2025-09-19 17:13:59
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Tunable and Switchable Multi-wavelength Erbium-Brillouin Random Fiber Laser Incorporating a Highly Nonlinear Fiber
摘要： In this communication, a recon?gurable feeding network is proposed for the design of a quad-polarization-agile antenna. By switching the PIN diodes, the four transmission modes with selected phase differences can be electrically tuned at two output ports. For each mode, the measured insertion loss of the feeding network is less than 0.8 dB at the operating frequency. Because of its compact size, the proposed feeding network can be further integrated with a dual-polarized aperture-coupled antenna, which can exhibit two orthogonal linear polarizations and two orthogonal circular polarizations. Measured results of the polarization-agile antenna are shown in detail, which verify its performance.
关键词： recon?gurable antenna,circular and linear polarization,recon?gurable feeding network,Aperture-coupled patch antenna,polarization-agile
更新于2025-09-19 17:13:59
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[IEEE 2019 Workshop on Recent Advances in Photonics (WRAP) - Guwahati, India (2019.12.13-2019.12.14)] 2019 Workshop on Recent Advances in Photonics (WRAP) - High-Speed Cavity Enhanced Silicon Photodetector on SiN-SOI Platform for Short Reach Optical Datacom
摘要： In this communication, a recon?gurable feeding network is proposed for the design of a quad-polarization-agile antenna. By switching the PIN diodes, the four transmission modes with selected phase differences can be electrically tuned at two output ports. For each mode, the measured insertion loss of the feeding network is less than 0.8 dB at the operating frequency. Because of its compact size, the proposed feeding network can be further integrated with a dual-polarized aperture-coupled antenna, which can exhibit two orthogonal linear polarizations and two orthogonal circular polarizations. Measured results of the polarization-agile antenna are shown in detail, which verify its performance.
关键词： recon?gurable antenna,circular and linear polarization,recon?gurable feeding network,Aperture-coupled patch antenna,polarization-agile
更新于2025-09-19 17:13:59
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Monolithic Linearly Polarized Nanosecond Fiber Laser with Record Peak Power and Near-Transform-Limited Linewidth
摘要： An all-fiberized linearly polarized nanosecond fiber laser with high peak power and near-transfrom-limited linewidth is demonstrated based on master oscillator power amplifier structure. Employing the polarization-maintaining fiber with large-mode-area Yb-doped tapered longitudinal geometry, short length and high concentration, the main amplifier possesses excellent performance for nonlinear effect suppression, including stimulated Brillouin scattering effect and self-phase modulation effect. As a result, an average output power of 8.8 W with the pulse duration of 3.8 ns is obtained at the repetition frequency of 80 kHz after the amplification, corresponding to the peak power of ~30 kW and the pulse energy of 110 uJ. The near- transform-limited linewidth is maintained, accompanying high polarization extinction ratio of more than 16 dB and near-diffraction-limited beam quality with M2 factor of 1.2. It is known to be the record output power of all-fiber linearly polarized ns fiber laser with transform-limited linewidth, to the best of our knowledge.
关键词： narrow linewidth,nanosecond fiber laser,tapered fiber,linear polarization
更新于2025-09-16 10:30:52
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Polarization of fluorescence radiation following electron impact excitation of ions immersed in strongly coupled plasmas
摘要： An investigation on the electron impact excitation and subsequent radiative decay process of He-like Fe24t ions immersed in strongly coupled plasmas is made, using the 1s2p 3;1P1 ! 1s2 1S0 characteristic lines as an example. The shielded nuclear potential of the uniform electron gas model (UEGM) type experienced by the electron is parameterized by the ion-sphere radius. For the target structure, accuracies of wave functions are justified by evaluating the energies of the relevant states. To serve as an independent check of the results, self-consistent calculations are carried out using the multiconfiguration Dirac-Fock relativistic configuration interaction method incorporating the same potential. For the impact excitation process, the UEGM potential is also employed to screen the projectile electron from the nucleus and target electrons. A distorted-wave method in the framework of the relativistic theory is developed to include the effect of plasma background, in which the continuum wave function of the projectile electron is evaluated by solving numerically the modified Dirac equations. The plasma effects on the total excitation cross section, magnetic sublevel cross section, and linear polarization of fluorescence radiation are investigated. The comparison with the available theoretical and experimental results is satisfactory.
关键词： UEGM potential,linear polarization,He-like Fe24t ions,electron impact excitation,strongly coupled plasmas,radiative decay
更新于2025-09-12 10:27:22
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Study of Grain Boundary Character || Control the Metal Grain Boundary Recrystallization Evolution by the Laser Radiation Electric Field Strength Direction Under Cyclic Thermal Loading
摘要： The spatial grating formation at metal surface under the linear polarized laser radiation action is briefly considered. The spatial grating periods are well described in framework of universal polariton model (UPM) and are well-defined physical quantities. The production of new-type gratings (quasi-gratings) at laser power densities lower than the metal melting threshold with power-dependent typical spatial scale and polarization-dependent orientation are discovered. The regularities of quasi-grating production are experimentally studied. The physical model of quasi-grating formation explaining the anisotropic character of metal recrystallization is suggested. The anisotropy is caused by the directed electron flux interaction with grain boundaries. The electron flux results from the drag effect of electrons by surface plasmon polaritons (SPPs). SPPs are excited by incident laser radiation on the surface irregularities including the grain boundaries. The volume analog of considered effect is the electroplastic one, and some of its regularities are considered.
关键词： grain boundary movement,laser radiation,electrons drag by surface plasmon polaritons,metal,electroplastic effect,surface plasmon polaritons,linear polarization,anisotropic recrystallization
更新于2025-09-11 14:15:04