Zeyong Wei

Tongji University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Zhanshan Wang

Tongji University

Xinbin Cheng

Tongji University

Yuancheng Fan

Northwestern Polytechnical University

Hongqiang Li

Shaoxing University

Chao Wu

Tongji University

Hongqiang Li

Tongji University

C. T. Chan

Hong Kong University of Science and Technology

Lingyun Xie

Tongji University

Siyu Dong

Tongji University

Jinlong Zhang

Guizhou University

Cooperative Institutions

Tongji University

111

Chinese Academy of Sciences

University of Chinese Academy of Sciences

Shanghai Jiao Tong University

Nanjing University of Aeronautics and Astronautics

University of Science and Technology of China

Northwestern Polytechnical University

Tsinghua University

Sun Yat-sen University

Zhejiang University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Geometric Phase Based Circular Array for Multimode Vortex Beam Generation

Annalen der Physik (2019)

Quan Li Chao Wu Xuan Liu Song Zhao Zhihui Zhang

Abstract A geometric phase model for electromagnetic radiating elements is proposed. By rotation of the radiating element, a frequency‐independent geometric phase occurs for circularly polarized components of radiation field along every direction in far field. In addition, the geometric phase is equal to the rotation angle for a circularly polarized source, which enables phase modulation ranging from 0 to 2π. In contrast, the Pancharatnam–Berry phase for circular polarization conversion components brought by optical element rotation is twice the rotation angle and is applicable only for the scattering waves propagating along the rotation axis. As a proof of principle, an antenna array is designed and fabricated in microwave regime to verify the phase modulation approach. Both the calculated and measured results verify that three different orbital angular momentum modes are generated simultaneously at 8.5 GHz and 11.5 GHz.

Stokes parameters

Optical vortex

Circular buffer

10.1002/andp.201900367

Cite

Citations (1)

Nanosecond laser damage characteristics of nodular defects in dielectric multilayers

Optical Interference Coatings (2013)

Xinbin Cheng Jinlong Zhang Tao Ding Zeyong Wei Hongqiang Li

Our recent research on damage mechanisms of artificial nodules in dielectric multilayers will be reviewed. The focus is on the influence of electric-field distributions on thermomechanical damage of nodules.

Nanosecond

10.1364/oic.2013.fb.1

Cite

Citations (0)

Achieving a high- Q response in metamaterials by manipulating the toroidal excitations

Physical review. A/Physical review, A (2018)

Yuancheng Fan Fuli Zhang Nian‐Hai Shen Quanhong Fu Zeyong Wei

The excitation of toroidal multipoles in metamaterials is investigated for a high-$Q$ response at a subwavelength scale. In this paper, we explore the optimization of toroidal excitations in a planar metamaterial comprised of asymmetric split ring resonators (ASRRs). It is found that the scattering power of a toroidal dipole can be remarkably strengthened by adjusting the characteristic parameter of ASRRs: an asymmetric factor. Interestingly, the improvement in toroidal excitation accompanies an increment of the $Q$ factor of the toroidal metamaterial; it is shown that both the scattering power of the toroidal dipole and the $Q$ factor increase more than one order by changing the asymmetric factor of ASRRs. The optimization in the excitation of a toroidal multipole provides an opportunity to further increase the $Q$ factor of the metamaterial and boost light-matter interactions at the subwavelength scale for potential applications in low-power nonlinear processing and sensitive photonic applications.

Q factor

10.1103/physreva.97.033816

Cite

Citations (80)

LBF:Learnable Bilateral Filter For Point Cloud Denoising

arXiv (Cornell University) (2022)

Huajian Si Zeyong Wei Zhe Zhu Honghua Chen Liang Dong

Bilateral filter (BF) is a fast, lightweight and effective tool for image denoising and well extended to point cloud denoising. However, it often involves continual yet manual parameter adjustment; this inconvenience discounts the efficiency and user experience to obtain satisfied denoising results. We propose LBF, an end-to-end learnable bilateral filtering network for point cloud denoising; to our knowledge, this is the first time. Unlike the conventional BF and its variants that receive the same parameters for a whole point cloud, LBF learns adaptive parameters for each point according its geometric characteristic (e.g., corner, edge, plane), avoiding remnant noise, wrongly-removed geometric details, and distorted shapes. Besides the learnable paradigm of BF, we have two cores to facilitate LBF. First, different from the local BF, LBF possesses a global-scale feature perception ability by exploiting multi-scale patches of each point. Second, LBF formulates a geometry-aware bi-directional projection loss, leading the denoising results to being faithful to their underlying surfaces. Users can apply our LBF without any laborious parameter tuning to achieve the optimal denoising results. Experiments show clear improvements of LBF over its competitors on both synthetic and real-scanned datasets.

Feature (linguistics)

Non-Local Means

10.48550/arxiv.2210.15950

Cite

Citations (0)

Scattering exceptional point in the visible

Light Science & Applications (2023)

Tao He Zhanyi Zhang Jingyuan Zhu Yuzhi Shi Zhipeng Li

Exceptional point (EP) is a special degeneracy of non-Hermitian systems. One-dimensional transmission systems operating at EPs are widely studied and applied to chiral conversion and sensing. Lately, two-dimensional systems at EPs have been exploited for their exotic scattering features, yet so far been limited to only the non-visible waveband. Here, we report a universal paradigm for achieving a high-efficiency EP in the visible by leveraging interlayer loss to accurately control the interplay between the lossy structure and scattering lightwaves. A bilayer framework is demonstrated to reflect back the incident light from the left side ( | r-1 | >0.999) and absorb the incident light from the right side ( | r+1 | < 10-4). As a proof of concept, a bilayer metasurface is demonstrated to reflect and absorb the incident light with experimental efficiencies of 88% and 85%, respectively, at 532 nm. Our results open the way for a new class of nanoscale devices and power up new opportunities for EP physics.

Degeneracy (biology)

Lossy compression

Visible spectrum

10.1038/s41377-023-01282-4

Cite

Citations (17)

Deep Algebraic Fitting for Multiple Circle Primitives Extraction from Raw Point Clouds

arXiv (Cornell University) (2022)

Zeyong Wei Honghua Chen Hao Tang Qian Xie Mingqiang Wei

The shape of circle is one of fundamental geometric primitives of man-made engineering objects. Thus, extraction of circles from scanned point clouds is a quite important task in 3D geometry data processing. However, existing circle extraction methods either are sensitive to the quality of raw point clouds when classifying circle-boundary points, or require well-designed fitting functions when regressing circle parameters. To relieve the challenges, we propose an end-to-end Point Cloud Circle Algebraic Fitting Network (Circle-Net) based on a synergy of deep circle-boundary point feature learning and weighted algebraic fitting. First, we design a circle-boundary learning module, which considers local and global neighboring contexts of each point, to detect all potential circle-boundary points. Second, we develop a deep feature based circle parameter learning module for weighted algebraic fitting, without designing any weight metric, to avoid the influence of outliers during fitting. Unlike most of the cutting-edge circle extraction wisdoms, the proposed classification-and-fitting modules are originally co-trained with a comprehensive loss to enhance the quality of extracted circles.Comparisons on the established dataset and real-scanned point clouds exhibit clear improvements of Circle-Net over SOTAs in terms of both noise-robustness and extraction accuracy. We will release our code, model, and data for both training and evaluation on GitHub upon publication.

Robustness

Data point

10.48550/arxiv.2204.00920

Cite

Citations (1)

Anomalous reflection with customized high-efficiency bandwidth

Optics Letters (2023)

Yuhang Dai Tao He Zeyong Wei Zhanshan Wang Xinbin Cheng

Anomalous reflection from metasurfaces with 100% efficiency at optical frequencies was not achieved until an all-dielectric quasi-three-dimensional subwavelength structure was proposed. The desired nonlocal control of light waves is realized by designing phase responses of multilayer films at a single wavelength. However, a high-efficiency bandwidth is not controllable by designing only the phase response at a single wavelength. Here, we propose the use of a multilayer metasurface to achieve anomalous reflection with a customized high-efficiency bandwidth. The interference of the successive light waves scattered from the structure at multiple wavelengths is controlled by phase dispersion regulation of multilayer films. As a proof of concept, two sets of multilayer films with different phase dispersions were designed to realize broadband (∼110 nm) and narrowband (∼15 nm) anomalous reflections, both with an efficiency of over 80%. The results offer a general strategy to design high-efficiency anomalous reflection with arbitrary bandwidth and might stimulate various potential applications for metadevices.

Narrowband

Reflection

10.1364/ol.480735

Cite

Citations (3)

Broadband efficient vortex beam generation with metallic helix array

Applied Physics Letters (2018)

Zhijie Gong Chao Wu Chaoqun Fang Song Zhao Anqi Sun

Vortex beams with orbital angular momentum are characterized by a helical phase front and a phase singularity at the beam center. Such beams have various intriguing applications, such as optical communications, particle trapping, and high resolution imaging. Generating a vortex beam by exploiting the geometric phase has attracted great interest, due to its spin-to-orbital conversion feature and device versatility. To meet the requirements of applications such as optical communications and make the devices more user-friendly, vortex beam generation needs to be efficient in a large frequency range. The efficient bandwidth of the optical element is critical here, since the geometric phase is frequency independent. In this work, we design and fabricate a broadband efficient reflective vortex beam generator based on a metallic helix array, which has a uniform efficient co-circular-polarization reflection property. Vortex beams with arbitrary topological charge can be generated with such devices. The measured efficiency of our device is above 58.4%, with the relative bandwidth of 64.52%.

Optical vortex

Light beam

10.1063/1.5039804

Cite

Citations (5)

Two-dimensional guided-mode resonance gratings with an etch-stop layer and high tolerance to fabrication errors

Optics Express (2022)

Jianyu Zhou Siyu Dong Zeyong Wei Jinlong Zhang Xiao Deng

Guided-mode resonance (GMR) bandpass filters have many important applications. The tolerance of fabrication errors that easily cause the transmission wavelength to shift has been well studied for one-dimensional (1D) anisotropic GMR gratings. However, the tolerance of two-dimensional (2D) GMR gratings, especially for different design architectures, has rarely been explored, which prevents the achievement of a high-tolerance unpolarized design. Here, GMR filters with common 2D zero-contrast gratings (ZCGs) were first investigated to reveal their differences from 1D gratings in fabrication tolerance. We demonstrated that 2D ZCGs are highly sensitive to errors in the grating linewidth against the case of 1D gratings, and the linewidth orthogonal to a certain polarization direction has much more influence than that parallel to the polarization. By analyzing the electromagnetic fields, we found that there was an obvious field enhancement inside the gratings, which could have a strong effect on the modes in the waveguide layer through the field overlap. Therefore, we proposed the introduction of an etch-stop (ES) layer between the gratings and the waveguide-layer, which can effectively suppress the interaction between the gratings and modal evanescent fields, resulting in 4-fold increased tolerance to the errors in the grating linewidth. Finally, the proposed etch-stop ZCGs (ES-ZCGs) GMR filters were experimentally fabricated to verify the error robustness.

Laser linewidth

Guided-mode resonance

Rigorous coupled-wave analysis

10.1364/oe.464065

Cite

Citations (1)

Broadband depolarized perfect Littrow diffraction with multilayer freeform metagratings

Optica (2023)

Siyu Dong Zhanyi Zhang Lingyun Xie Jingyuan Zhu Haigang Liang

Littrow diffraction, the ability to reflect light back along incident direction, is a key functionality of retroreflectors, exhibiting wide applications in nanophotonics. However, retroreflectors have hitherto low working efficiencies and narrow bandwidths, and work only for a specific polarization, being unfavorable for integration-optics applications. Here, we propose a type of metagrating consisting of an all-dielectric Bragg reflector and a periodic metasurface with freeform-shaped dielectric resonators, which enables broadband depolarized perfect Littrow diffraction at optical frequencies. The physics is governed by exact cancellations of specular reflections contributed by two Bragg modes in metagratings, enabled by careful structural optimization to yield the desired reflection-phase difference of Bragg modes within a wide frequency band and for two polarizations. As a proof of concept, we experimentally demonstrate retroreflections with unpolarized absolute efficiency higher than 98% (99% in design) at 1030–1090 nm using multilayer freeform metagratings. Our results pave the way for numerous applications based on high-efficiency Littrow diffraction (e.g., spectral laser beam combining), which is not bonded to a specific polarization or frequency.

Retroreflector

Diffraction efficiency

10.1364/optica.486332

Cite

Citations (20)