- 标题
- 摘要
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- 实验方案
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Dual-Polarized Phased Array Based Polarization State Modulation for Physical-Layer Secure Communication
摘要： In this paper, a dual-polarized phased array based polarization state modulation method is proposed to enhance the physical-layer security in millimeter-wave (mm-wave) communication systems. Indeed, we utilize two polarized beams to transmit the two components of the polarized signal, respectively. By randomly selecting the transmitting antennas, both the amplitude and the phase of two beams vary randomly in undesired directions, which lead to the PM constellation structure distortion in side lobes, thus the transmission security is enhanced since the symbol error rate increases at the eavesdropper side. To enhance the security performance when the eavesdropper is close to the legitimate receiver and located in main beam, the artificial noise based on the orthogonal vector approach is inserted randomly between two polarized beams, which can further distort the constellation structure in undesired directions and improve the secrecy capacity in main beam as well. Finally, theoretical analysis and simulation results demonstrate the proposed method can improve the transmission security in mm-wave communication systems.
关键词： dual-polarized array,polarization state modulation,physical-layer secure communication
更新于2025-09-23 15:22:29
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Adaptive AoA and Polarization Estimation for Receiving Polarized mmWave Signals
摘要： This paper proposes a novel hybrid dual-polarized antenna array which exploits two orthogonally-collocated dipoles to capture the full power of a polarized millimeter wave signal. To maximize the received signal-to-noise ratio (SNR), we study the adaptive angle-of-arrival and polarization state estimation, and develop a differential beam tracking algorithm and a cross-correlation-to-power ratio polarization tracking algorithm for interleaved hybrid dual-polarized arrays. Simulation results verify the superior performance of the proposed algorithms, and confirm the significant improvement of SNR obtained by using the proposed array and algorithms.
关键词： angle-of-arrival estimation,Hybrid dual-polarized antenna array,polarization state estimation,mmWave
更新于2025-09-23 15:21:21
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Polarization-enabled tunable focusing by visible-light metalenses with geometric and propagation phase
摘要： Flat metalenses with tunable focal length have wide applications in modern optical systems with high integration requirement. Here, by combining propagation phase and geometric phase, we numerically realize a metalens with a tunable focal length by controlling the polarization state of incident light. The tuning range can be as large as 15λ at the designer wavelength. Furthermore, the tunable performance can operate at the entire visible band with an ef?ciency over 35%. We believe that the proposed polarization-enabled tunable focusing metalens will ?nd signi?cant applications in imaging and sensing applications.
关键词： tunable focusing,metalens,polarization state,geometric phase
更新于2025-09-23 15:19:57
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Using the Belinfante momentum to retrieve the polarization state of light inside waveguides
摘要： current day high speed optical communication systems employ photonic circuits using platforms such as silicon photonics. In these systems, the polarization state of light drifts due to effects such as polarization mode dispersion and nonlinear phenomena generated by photonic circuit building blocks. As the complexity, the number, and the variety of these building blocks grows, the demand increases for an in-situ polarization determination strategy. Here, we show that the transfer of the Belinfante momentum to particles in the evanescent field of waveguides depends in a non-trivial way on the polarization state of light within that waveguide. Surprisingly, we find that the maxima and minima of the lateral force are not produced with circularly polarized light, corresponding to the north and south poles of the Poincaré sphere. Instead, the maxima are shifted along the great circle of the sphere due to the phase differences between the scattered TE and TM components of light. This effect allows for an unambiguous reconstruction of the local polarization state of light inside a waveguide. Importantly, this technique depends on interaction with only the evanescent tails of the fields, allowing for a minimally invasive method to probe the polarization within a photonic chip.
关键词： waveguides,Poincaré sphere,Belinfante momentum,evanescent field,optical communication,photonic chip,TE and TM components,silicon photonics,polarization state
更新于2025-09-19 17:13:59
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Detecting polarization state of arbitrary polarized light by chiral plasmonic lenses with distributed nanoslits
摘要： We devise three chiral plasmonic lenses (PLs) with distributed nanoslits for detecting the complete state of polarization of an arbitrary polarized light. A double-ring arrayed nanocrosses-based plasmonic lens is proposed to focus the surface plasmon polaritons excited by the two circularly polarized components of the incident light, thus enabling the phase difference between the two components to be retrieved. Two Archimedes-spiral arrayed nanoslits-based PLs with opposite chirality are designed to detect the relative strength of the two components. The focusing properties of the three structures are theoretically derived and numerically investigated, demonstrating the effectiveness of the proposed method.
关键词： surface plasmon polaritons,polarization state,nanoslits,chiral plasmonic lenses
更新于2025-09-16 10:30:52
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Evidence of depolarization and ellipticity of high harmonics driven by ultrashort bichromatic circularly?polarized fields
摘要： High harmonics generated by counter-rotating laser fields at the fundamental and second harmonic frequencies have raised important interest as a table-top source of circularly polarized ultrashort extreme-ultraviolet light. However, this emission has not yet been fully characterized: in particular it was assumed to be fully polarized, leading to an uncertainty on the effective harmonic ellipticity. Here we show, through simulations, that ultrashort driving fields and ultrafast medium ionization lead to a breaking of the dynamical symmetry of the interaction, and consequently to deviations from perfectly circular and fully polarized harmonics, already at the single-atom level. We perform the complete experimental characterization of the polarization state of high harmonics generated along that scheme, giving direct access to the ellipticity absolute value and sign, as well as the degree of polarization of individual harmonic orders. This study allows defining optimal generation conditions of fully circularly polarized harmonics for advanced studies of ultrafast dichroisms.
关键词： circularly polarized fields,high harmonics,ultrafast dichroisms,ultrashort pulses,polarization state
更新于2025-09-10 09:29:36
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Imaging and visualization of the polarization state of the probing beam in polarization-sensitive optical coherence tomography
摘要： We propose a simple and ef?cient method of color-encoded Stokes parameters to visualize the polarization states for polarization-sensitive optical coherence tomography (PS-OCT) of biological tissue. In this method, polarization states of the probing light are detected and described in the Stokes domain. Three primary colors of red, green, and blue are used to code Stokes parameters of Q, U, and V, respectively, which can be used to represent and visualize each unique polarization state. A strategy that uses the polarization state as the PS-OCT imaging parameter is ?rst introduced to obtain high contrast images of the birefringent samples. Then, color-based automatic segmentation of birefringent components from 3D scanned tissue volume is proposed to isolate the network of the 3D nerve bundles in a mouse brain without cutting the brain into slices. Experimental validation and demonstrations are given by imaging ex vivo mouse tail and brain tissues to show the usefulness of proposed polarization state imaging and segmentation methods.
关键词： automatic segmentation,Stokes parameters,birefringent tissue,polarization-sensitive optical coherence tomography,polarization state imaging
更新于2025-09-04 15:30:14