- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
A shared aperture 1-bit metasurface for orbital angular momentum multiplexing
摘要： In this letter, a shared aperture 1-bit metasurface for orbital angular momentum (OAM) multiplexing is studied. A phased array antenna fed by the phase shift network is embedded on the reflective aperture of the 1-bit metasurface. The proposed device can work on reflectarray mode from 7.1GHz to 7.5GHz and phased array mode from 7GHz to 7.5GHz. Correspondingly, OAM vortex beam with topological charge l = -1 and l = 1 can be generated. The transmission coefficient between the two working modes is below -30dB and the envelop correlation coefficient (ECC) is quite close to 0, which reveals the excellent isolation and diversity performance. A prototype of the proposed device is fabricated and tested. The measured S parameters and radiation patterns agree well with the simulation results.
关键词： phased array,reflectarray,metasurface,Orbital angular momentum (OAM) multiplexing
更新于2025-09-23 15:22:29
-
High-Efficiency Planar Reflectarray with Small-size for OAM Generation at Microwave Range
摘要： In this paper, a high-efficiency planar reflectarray with a small size 3.87λ0 × 3.87λ0 is designed, which can effectively convert arbitrary polarized waves to orbital angular momentum (OAM) waves with desired mode number and beam direction. The two concentric rings with a small size 0.38λ0 × 0.38λ0 compose the unit, which can cover the phase shifting range 360o by adjusting the ring radius. Though the developed reflectarray is much smaller than that of published ones, it can produce beams with the similar performance as large antennas. The advantages are as follows: high efficiency 22.6%, which is superior to published OAM reflectarrays, high gain 15.4 dBi, narrow divergence angle 9o, high purity, good stability, polarization insensitivity, planar structure, and easy fabrication. Using this reflective metasurface, we designed the following OAM beams: (1) OAM mode l = 1, 2, 3, 4 at (θ = 0o, φ = 0o). (2) l = 1 at (θ = 45o, φ = 180o). (3) l = 1 at (θ = 45o, φ = 270o). The above advantages are proved by the following analysis: (1) The magnitude and phase distributions in the near field. (2) The purity analysis. (3) The radiation pattern in the far field.
关键词： Orbital angular momentum (OAM),high efficiency,vortex beam,planar reflectarray antenna
更新于2025-09-19 17:15:36
-
Hybrid Entangled States With Multi-Degree of Freedom and High Purity for Internet of Vehicles
摘要： The development of intelligent Internet of vehicles (IoV) is based on communication technology, especially the quantum communication of hybrid entangled states based on orbital angular momentum (OAM). The quantum key distribution (QKD) method is demonstrated using hybrid entangled states with multi-degree of freedom and high purity based on OAM. First, the polarization entangled photon pairs are produced by two type I BBO crystals by means of spontaneous parametric down-conversion (SPDC). The polarization-OAM hybrid entangled states are created by q-plate (QP) to realize QKD. It is found that the polarization entangled photon pairs have the characteristics of OAM. A single mode fiber (SMF) is proposed to filter the topological charge non-zero photons and purify the polarization entangled photon pairs. Then the purification setup with M-Z interferometer and beam rotator (BR) is presented which can purify the polarization-OAM hybrid entangled states. The high purity polarization-OAM hybrid entangled states are implemented, and the QP conversion rate of 3 secondary feedbacks is 99.84% theoretically. Analysis indicates that precise purity polarization-OAM hybrid entangled state can increase the fidelity of information and improve the anti-interference ability in this program without mutually unbiased bases (MUBs). The photon utilization rate, energy-efficient and low-latency communication can be greatly improved by using the OAM carrying information.
关键词： hybrid entanglement,orbital angular momentum (OAM),coincidence measurement,high purity,Internet of vehicles (IoV),low-latency
更新于2025-09-19 17:13:59
-
Modeling and Optimization of Vortex Modes Propagation in Rectangular Dielectric Waveguides
摘要： We study analytically and numerically the possibility of vortex modes propagation over planar dielectric rectangular waveguides, and consider the problem of waveguide geometry optimization for the support of vortex modes. The results show, that theoretically rectangular waveguides can provide transmission of quasi-TE and quasi-TM modes with high purity states of orbital angular momentum (OAM) in the dominant ?eld component. However, only for the quasi-generate mode of azimuthal order ±1 the constituent eigenmodes can propagate in a phase-matched regime, and the vortex modes of higher azimuthal orders can propagate only with a certain beat length. Moreover, as the target azimuthal order increases, the normalized power of the corresponding OAM state in the modal superposition decreases. The analytical predictions have been veri?ed by numerical electromagnetic simulations of silicon nitride waveguides providing ?eld distributions and OAM spectra of the corresponding modal superpositions.
关键词： integrated photonics,silicon nitride,optical waveguides,Optical orbital angular momentum (OAM)
更新于2025-09-16 10:30:52
-
Scintillation of laser beams carrying orbital angular momentum propagating in a near-maritime environment
摘要： Laser beams carrying orbital angular momentum (OAM) were propagated in a near-maritime environment along an 890 meter link across the Severn River at the United States Naval Academy. The OAM beams were generated using green light ( ?? = 532 nm) and etched spiral phase plates with different topological charges. The light intensity fluctuations of Gaussian and beams carrying OAM with topological charges of 1, 6, and 8 were measured and the scintillation indices of each beam were compared. Additionally, atmospheric turbulence was measured using a co-aligned scintillometer along the 890 meter propagation path. During testing, a wide range of atmospheric conditions occurred and the refractive index structure parameter measurements ranged from 5 × 10?14 down to 5 × 10?15 m ???∕??. Our measurements of transmitted voltage in the radial intensity across the maritime link, and calculated scintillation index, for the Gaussian beam and laser beams carrying OAM indicate a weak reduction in scintillation index for increasing topological charge. To reduce the measurement uncertainty and improve upon statistical significance of our findings, additional testing is needed.
关键词： Orbital angular momentum,OAM,Scintillation,Laser propagation,Near-maritime environment
更新于2025-09-12 10:27:22
-
[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 Multiple Up-Converted OAM States from a Tunable Optical Vortex Parametric Laser Source
摘要： Optical vortices with a ring-shaped spatial form and an orbital angular momentum (OAM) of ?φ, arising from their helical wavefronts characterized by an azimuthal phase, exp(i?φ) (where ? is an integer termed the topological charge), have been widely exploiting a variety of research fields. These include optical trapping and manipulation, fluorescent microscopes with a high spatial resolution beyond the diffraction limit and materials processing. The aforementioned applications strongly desire wavelength-tunability and OAM-versatility to optical vortex sources. In this presentation, we report on the first generation of a signal output having multiple up-converted OAM states with ?(cid:3046) =3~5 (higher OAM than that of pump) from a nanosecond 2nd-order vortex (?(cid:3043) = 2) pumped singly resonant optical parametric oscillator (OPO) with a simple compact cavity configuration. The resulting idler exhibited negative OAM states with ?(cid:3036) =-1~-3.
关键词： Orbital angular momentum,OAM states,Wavelength-tunability,Optical vortices,Optical parametric oscillator
更新于2025-09-11 14:15:04
-
Analysis of Bending-Induced Degradation of Orbital Angular Momentum Modes in Optical Fibers
摘要： In this work, bending-induced deterioration of orbital angular momentum (OAM) modes in ring core ?ber (RCF), photonic crystal ?ber (PCF), and vortex ?ber (VF) was theoretically investigated: Bending losses, coupling losses, and intermodal crosstalk at the interface between straight and bent optical ?bers were investigated from the modal analysis of those three types of OAM mode ?bers. In addition, the degradation of a topological charge number of an OAM mode due to the bending-induced birefringence and horizontal mode asymmetry was also investigated. Our investigation revealed that, in all aspects, the PCF is most robust to bending among the three types of optical ?bers, and the most serious bending-induced problem in the VF and the RCF is the degradation of the topological charge number. The allowed minimum bending radii of VF and RCF appeared to be ~15 and ~45 mm, respectively, for the speci?c structures considered in this work. We expect that the methodology and results of our quantitative analysis on bending-induced degradation of OAM modes will be of great use in the design of OAM mode ?bers for practical use.
关键词： ring core ?ber,photonic crystal ?ber,topological charge number,orbital angular momentum (OAM),vortex ?ber,?ber bending e?ect
更新于2025-09-11 14:15:04
-
[IEEE 2019 IEEE Photonics Conference (IPC) - San Antonio, TX, USA (2019.9.29-2019.10.3)] 2019 IEEE Photonics Conference (IPC) - Shaping Optical Fibers to Mode Division Multiplex without MIMO
摘要： MIMO complexity can be reduced or avoided completely by proper design of the few mode optical fiber used for mode division multiplexing. Our focus is high index contrast fibers that avoid the formation of scalar modes, to favor vector modes with more limited modal interactions.
关键词： SDM,orbital angular momentum,OAM,spatial division multiplexing,MDM,mode division multiplexing
更新于2025-09-11 14:15:04
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - A Novel Imaging Formation of Electromagnetic Vortex Sar with Time-Variant Orbital-Angular-Momentum
摘要： In recent years, electromagnetic vortex waves carrying orbital angular momentum (OAM) arouse extensive attention in remote sensing imaging fields. However, most of the researches concentrate on the staring imaging mode, where the radar is motionless relative to the targets. We establish a novel system operation mode based on the principle of synthetic aperture radar (SAR). The echo model upon this novel operation mode is established and the new imaging method modified from the back-projection (BP) algorithm is deduced. Simulation and image evaluation results demonstrate the validation of the proposed method and OAM-based SAR system can be utilized in the SAR data acquisition and signal processing fields.
关键词： Orbital angular momentum (OAM),back-projection (BP) algorithm,synthetic aperture radar (SAR),electromagnetic (EM) vortex
更新于2025-09-09 09:28:46
-
An Electronically Mode Reconfigurable Orbital Angular Momentum Array Antenna
摘要： In this paper, an array antenna for generating multi-mode orbital angular momentum (OAM) vortex waves and having electrically controlled mode reconfigurable function is proposed. The proposed antenna is based on a reconfigurable feed network (RFN) consisting of multiple PIN diodes as reconfigurable switches, a direct current (dc) control board and a 2 × 4 radial uniform circular array. By controlling the coding sequence of the corresponding PIN diode dc bias voltage on the RFN using a programmable microcontroller, the OAM modes generated by the proposed antenna can be dynamically reconfigured between l = 0, ±1, and ±2. Moreover, the OAM beams can be generated in a wide frequency band of 5.5–6.1 GHz and 5.65–6.1GHz for l = ± 1, ±2 modes and l = 0 mode, respectively. The prototype of the proposed antenna is simulated and fabricated to validate the proposed design. Both far-field and near-field experiments were performed to verify the feasibility of the proposed design. The results of the numerical simulation and measurement have good agreement with each other.
关键词： orbital angular momentum (OAM),array antenna,Reconfigurable,PIN diodes
更新于2025-09-09 09:28:46