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Negative refraction of ultra-squeezed in-plane hyperbolic designer polaritons

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Photonics Research 2021年第8期9卷 1540-1549页

作者： QIAOLU CHEN YIHAO YANG LI ZHANG JIALIN CHEN MIN LI XIAO LIN RUJIANG LI ZUOJIA WANG BAILE ZHANG HONGSHENG CHEN Interdisciplinary Center for Quantum Information State Key Laboratory of Modern Optical InstrumentationZJU-Hangzhou Global Scientific and Technological Innovation CenterZhejiang UniversityHangzhou 310027China International Joint Innovation Center Key Laboratory of Advanced Micro/Nano Electronic Devices&Smart Systems of ZhejiangThe Electromagnetics Academy at Zhejiang UniversityZhejiang UniversityHaining 314400China Division of Physics and Applied Physics School of Physical and Mathematical SciencesNanyang Technological UniversitySingapore 637371Singapore Centre for Disruptive Photonic Technologies The Photonics InstituteNanyang Technological UniversitySingapore 639798Singapore

The in-plane negative refraction of high-momentum(i.e.,high-k)photonic modes could enable many applications such as imaging,focusing,and waveguiding in a planar platform at deep-subwavelength ***,its practical implementation in experiments remains elusive so *** we propose a class of hyperbolic metasurfaces,which is characterized by an anisotropic magnetic sheet conductivity and can support the in-plane ultrahigh-k magnetic designer *** on such metasurfaces,we report the experimental observation of the all-angle negative refraction of designer polaritons at extremely deep-subwavelength ***,we directly visualize the designer polaritons with hyperbolic ***,for these hyperbolic polaritons,we find that their squeezing factor is *** be specific,it can be up to 129 in the experiments,an ultra-high value exceeding those in naturally hyperbolic *** work may pave a way toward exploring the extremely high confinement and unusual propagation of magnetic designer polaritons over monolayer or twisted bilayer hyperbolic metasurfaces.

关键词： hyperbolic refraction polar

Reconfigurable Three-Dimensional Thermal Dome

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arXiv 2023年

作者： Zhou, Yuhong Yang, Fubao Xu, Liujun Zhuang, Pengfei Wang, Dong Ouyang, Xiaoping Li, Ying Huang, Jiping Fudan University Shanghai200438 China Graduate School of China Academy of Engineering Physics Beijing100193 China School of Materials Science and Engineering Xiangtan University Xiangtan411105 China Interdisciplinary Center for Quantum Information State Key Laboratory of Modern Optical Instrumentation ZJU-Hangzhou Global Scientific and Technological Innovation Center Zhejiang University Hangzhou310027 China International Joint Innovation Center Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang The Electromagnetics Academy of Zhejiang University Zhejiang University Haining314400 China

Thermal metamaterial represents a groundbreaking approach to control heat conduction, and, as a crucial component, thermal invisibility is of utmost importance for heat management. Despite the flourishing development of thermal invisibility schemes, they still face two limitations in practical ap plications. First, objects are typically completely enclosed in traditional cloaks, making them difficult to use and unsuitable for objects with heat sources. Second, although some theoretical proposals have been put forth to change the thermal conductivity of materials to achieve dynamic invisibility, their designs are complex and rigid, making them unsuitable for large-scale use in real three-dimensional spaces Here, we propose a concept of a thermal dome to achieve three-dimensional invisibility. Our scheme includes an open functional area, greatly enhancing its usability and applicability. It features a reconfigurable structure, constructed with simple isotropic natural materials, making it suitable for dynamic requirements. The performance of our reconfigurable thermal dome has been confirmed through simulations and experiments, consistent with the theory. The introduction of this concept can greatly advance the development of thermal invisibility technology from theory to engineering and provide inspiration fo other physical domains, such as direct current electric fields and magnetic fields. Copyright © 2023, The Authors. All rights reserved.

关键词： Metamaterials

Chiral and non-chiral swift mode conversion near an exceptional point with adiabaticity engineering

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arXiv 2023年

作者： Wang, Dong Huang, Wen-Xi Zhou, Bo Yu, Wenduo Cao, Pei-Chao Peng, Yu-Gui Zhou, Zheng-Yang Chen, Hongsheng Zhu, Xue-Feng Li, Ying State Key Laboratory of Extreme Photonics and Instrumentation ZJU-Hangzhou Global Scientific and Technological Innovation Center Zhejiang University Hangzhou310027 China International Joint Innovation Center The Electromagnetics Academy Zhejiang University Haining314400 China Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang Jinhua Institute Zhejiang University Jinhua321099 China Shaoxing Institute Zhejiang University Shaoxing312000 China School of Physics and Innovation Institute Huazhong University of Science and Technology Wuhan430074 China Key Laboratory of Optical Field Manipulation of Zhejiang Province Department of Physics Zhejiang Sci-Tech University Hangzhou310018 China

The eigenvalue of a non-Hermitian Hamiltonian often forms a self-intersecting Riemann surface, leading to a unique mode conversion phenomenon when the Hamiltonian evolves along certain loop paths around an exceptional point (EP). However, two fundamental problems exist with the conventional scheme of EP encircling: the speed of mode conversion is restricted by the adiabatic requirement, and the chirality cannot be freely controlled. Here, we introduce a method which dynamically engineers the adiabaticity in the evolution of non-Hermitian Hamiltonians that allows for both chiral and non-chiral mode conversion on the same path. Our method is based on quantifying and controlling the instantaneous adiabaticity, allowing for non-uniform evolution throughout the entire path. We apply our method into the microwave waveguide system and by optimizing the distributed adiabaticity along the evolution loop, we achieve the same quality of mode conversion as conventional quasi-adiabatic evolution in only one-fourth of the time. Our approach provides a comprehensive and universal solution to address the speed and chirality challenges associated with EP encircling. It also facilitates the dynamic manipulation and regulation of non-adiabatic processes, thereby accelerating the operation and allowing for a selection among various mode conversion patterns. © 2023, CC BY.

关键词： Hamiltonians

In-Situ Electrostatic Field Regulating the Recrystallization Behavior of P(Vdf-Trfe) Films with High Β-Phase Content and Enhanced Piezoelectric Properties

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SSRN

SSRN 2022年

作者： Lv, Fu Lin, Jiamin Zhou, Zheng Hong, Zijian Wu, Yongjun Ren, Zhaohui Zhang, Qilong Dong, Shurong Luo, Jikui Shi, Junhui Chen, Ruimin Liu, Bing Su, Yuanjie Huang, Yuhui School of Materials Science and Engineering State Key Laboratory of Silicon Materials Cyrus Tang Center for Sensor Materials and Applications Zhejiang University Zhejiang Hangzhou310027 China School of Materials Science and Engineering State Key Lab of Silicon Materials Zhejiang University Zhejiang Hangzhou310027 China College of Information Science and Electronic Engineering Key Lab of Advanced Micro Nano Electronic Devices & Smart Systems of Zhejiang Zhejiang University Zhejiang Hangzhou310027 China Zhejiang Lab Zhejiang Hangzhou311121 China College of Electronic Information and Engineering Hangzhou Dianzi University Zhejiang Hangzhou310018 China School of Optoelectronic Science and Engineering University of Electronic Science and Technology of China Sichuan Chengdu610054 China

Fabrication of flexible piezoelectric polymers is essential for the development of wearable biosensors. Nevertheless, the piezoelectric coefficient of polymers is usually an order of magnitude lower than the inorganic piezoelectric materials, which limits the miniature of the devices. Herein, a simple and cost-effective technique is proposed by applying an electrostatic field to in-situ regulate the recrystallization behavior of the poly(vinylidene fluoride-trifluorethylene) (P(VDF-TrFE)) film during the thermal annealing and recrystallization stage. Significantly enhanced properties are obtained, including a large piezoelectric coefficient (d 33 ~30.7 pC/N) and a high voltage sensitivity of 167.12 mV/kPa. The outstanding performance is mainly attributed to the applied electrostatic field maintained during the film growth stage, which promotes the generation of nucleation sites for the polar β lamellae crystals. A wireless sensor system is further established with the obtained P(VDF-TrFE) film, demonstrating great potential applications in movement monitoring. The proposed facile approach could potentially be applied to the large-scale production of polymer films with excellent piezoelectric properties for flexible wireless biosensing device applications. © 2022, The Authors. All rights reserved.

关键词： Piezoelectricity

Non-Hermitian Dirac cones with valley-dependent lifetimes

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arXiv 2024年

作者： Xie, Xinrong Ma, Fei Rui, W.B. Dong, Zhaozhen Du, Yulin Xie, Wentao Zhao, Y.X. Chen, Hongsheng Gao, Fei Xue, Haoran State Key Laboratory of Extreme Photonics and Instrumentation International Joint Innovation Center The Electromagnetics Academy Zhejiang University Zhejiang University Haining314400 China ZJU-Hangzhou Global Scientific and Technological Innovation Center Zhejiang University Hangzhou310027 China Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang Jinhua Institute of Zhejiang University Zhejiang University Jinhua321099 China Shaoxing Institute of Zhejiang University Zhejiang University Shaoxing312000 China Department of Physics HKU-UCAS Joint Institute for Theoretical and Computational Physics at Hong Kong The University of Hong Kong Pokfulam Road Hong Kong HK Institute of Quantum Science & Technology The University of Hong Kong Pokfulam Road Hong Kong Department of Physics The Chinese University of Hong Kong Shatin Hong Kong

Relativistic quasiparticles emerging from band degeneracies in crystals play crucial roles in the transport and topological properties of materials and metamaterials. Quasiparticles are commonly described by Hermitian Hamiltonians, with non-Hermiticity usually considered detrimental. In this work, we show that such an assumption of Hermiticity can be lifted to bring quasiparticles into non-Hermitian regime. We propose a concrete lattice model containing two Dirac cones with valley-dependent lifetimes. The lifetime contrast enables an ultra-strong valley selection rule: only one valley can survive in the long-time limit regardless of the excitation, lattice shape and other details. This property leads to an effective parity anomaly with a single Dirac cone and offers a simple way to generate vortex states. Additionally, extending non-Hermitian features to boundaries generates valley kink states with valley-locked lifetimes, making them effectively unidirectional and more resistant against inter-valley scattering. All these phenomena are experimentally demonstrated in a non-Hermitian electric circuit lattice. Copyright © 2024, The Authors. All rights reserved.

关键词： Topology

Demonstration of topological wireless power transfer

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Science Bulletin 2021年第10期66卷 974-980,M0003页

作者： Li Zhang Yihao Yang Zhao Jiang Qiaolu Chen Qinghui Yan Zhouyi Wu Baile Zhang Jiangtao Huangu Hongsheng Chen Interdisciplinary Center for Quantum Information State Key Laboratory of Modern Optical InstrumentationCollege of Information Science and Electronic EngineeringZhejiang UniversityHangzhou 310027China ZJU-Hangzhou Global Science and Technology Innovation Center Key Laboratory of Advanced Micro/Nano Electronic Devices&Smart Systems of ZhejiangZhejiang UniversityHangzhou 310027China International Joint Innovation Center ZJU-UIUC InstituteZhejiang UniversityHaining 314400China Division of Physics and Applied Physics School of Physical and Mathematical SciencesNanyang Technological UniversitySingapore 637371Singapore Centre for Disruptive Photonic Technologies The Photonics InstituteNanyang Technological UniversitySingapore 639798Singapore Laboratory of Applied Research on Electromagnetics(ARE) Zhejiang UniversityHangzhou 310027China

Recent advances in non-radiative wireless power transfer(WPT)technique essentially relying on magnetic resonance and near-field coupling have successfully enabled a wide range of ***,WPT systems based on double resonators are severely limited to short-or mid-range distance,due to the deteriorating efficiency and power with long transfer *** systems based on multi-relay resonators can overcome this problem,which,however,suffer from sensitivity to perturbations and fabrication ***,we experimentally demonstrate a concept of topological wireless power transfer(TWPT),where energy is transferred efficiently via the near-field coupling between two topological edge states localized at the ends of a one-dimensional radiowave topological *** a TWPT system can be modelled as a parity-time-symmetric Su-Schrieffer-Heeger(SSH)chain with complex boundary ***,the coil configurations are judiciously designed,which significantly suppress the unwanted cross-couplings between nonadjacent coils that could break the chiral symmetry of the SSH *** tuning the inter-and intra-cell coupling strengths,we theoretically and experimentally demonstrate high energy transfer efficiency near the exceptional point of the topological edge states,even in the presence of *** combination of topological metamaterials,non-Hermitian physics,and WPT techniques could promise a variety of robust,efficient WPT applications over long distances in electronics,transportation,and industry.

关键词： Wireless power transfer Topological metamaterials Exceptional point Su-Schrieffer-Heeger model

Observation of vortex-string chiral modes in metamaterials

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arXiv 2023年

作者： Ma, Jingwen Jia, Ding Zhang, Li Guan, Yi-Jun Ge, Yong Sun, Hong-Xiang Yuan, Shou-Qi Chen, Hongsheng Yang, Yihao Zhang, Xiang Faculties of Science and Engineering The University of Hong Kong Hong Kong Interdisciplinary Center for Quantum Information State Key Laboratory of Extreme Photonics and Instrumentation ZJU-Hangzhou Global Scientific and Technological Innovation Center Zhejiang University Hangzhou310027 China Research Center of Fluid Machinery Engineering and Technology School of Physics and Electronic Engineering Jiangsu University Zhenjiang212013 China International Joint Innovation Center The Electromagnetics Academy Zhejiang University Zhejiang University Haining314400 China Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang Jinhua Institute Zhejiang University Zhejiang University Jinhua321099 China Shaoxing Institute of Zhejiang University Zhejiang University Shaoxing312000 China State Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences Beijing100190 China

As a hypothetical topological defect in the geometry of spacetime, vortex strings play a crucial role in shaping the clusters of galaxies that exist today, and their distinct features can provide observable clues about the early universe’s evolution. A key feature of vortex strings is that they can interact with Weyl fermionic modes and support topological chiral-anomaly states with massless dispersions at the core of strings. To date, despite many attempts to detect vortex strings in astrophysics or to emulate them in artificially created systems, observation of these topological vortex-string chiral modes remains experimentally elusive. Here we report the experimental observation of such vortex-string chiral modes using a metamaterial system. This is implemented by inhomogeneous perturbation of a Yang-monopole phononic metamaterial. The measured linear dispersion and modal profiles confirm the existence of topological modes bound to and propagating along the vortex string with the chiral anomaly. Our work not only provides a platform for studying diverse cosmic topological defects in astrophysics but also offers intriguing device applications as topological fibres in signal processing and communication *** Codes No © 2023, CC BY.

关键词： Vortex flow

Real higher-order Weyl photonic crystal

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Nature Communications 2023年第1期14卷 6636页

作者： Pan, Yuang Cui, Chaoxi Chen, Qiaolu Chen, Fujia Zhang, Li Ren, Yudong Han, Ning Li, Wenhao Li, Xinrui Yu, Zhi-Ming Chen, Hongsheng Yang, Yihao Interdisciplinary Center for Quantum Information State Key Laboratory of Extreme Photonics and Instrumentation ZJU-Hangzhou Global Scientific and Technological Innovation Center Zhejiang University Hangzhou 310027 China International Joint Innovation Center The Electromagnetics Academy at Zhejiang University Zhejiang University Haining 314400 China Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang Jinhua Institute of Zhejiang University Zhejiang University Jinhua 321099 China Shaoxing Institute of Zhejiang University Zhejiang University Shaoxing 312000 China Centre for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE) School of Physics Beijing Institute of Technology Beijing 100081 China Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems School of Physics Beijing Institute of Technology Beijing 100081 China

Higher-order Weyl semimetals are a family of recently predicted topological phases simultaneously showcasing unconventional properties derived from Weyl points, such as chiral anomaly, and multidimensional topological phenomena originating from higher-order topology. The higher-order Weyl semimetal phases, with their higher-order topology arising from quantized dipole or quadrupole bulk polarizations, have been demonstrated in phononics and circuits. Here, we experimentally discover a class of higher-order Weyl semimetal phase in a three-dimensional photonic crystal (PhC), exhibiting the concurrence of the surface and hinge Fermi arcs from the nonzero Chern number and the nontrivial generalized real Chern number, respectively, coined a real higher-order Weyl PhC. Notably, the projected two-dimensional subsystem with k_z = 0 is a real Chern insulator, belonging to the Stiefel-Whitney class with real Bloch wavefunctions, which is distinguished fundamentally from the Chern class with complex Bloch wavefunctions. Our work offers an ideal photonic platform for exploring potential applications and material properties associated with the higher-order Weyl points and the Stiefel-Whitney class of topological phases. © 2023, Springer Nature Limited.

关键词：

Experimental Realization of a Superdispersion-Enabled Ultrabroadband Terahertz Cloak (vol 34, 2205053, 2022)

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advanced MATERIALS 2022年第47期34卷 2209380-2209380页

作者： Cai, Tong Zheng, Bin Lou, Jing Shen, Lian Yang, Yihao Tang, Shiwei Li, Erping Qian, Chao Chen, Hongsheng Interdisciplinary Center for Quantum Information State Key Laboratory of Modern Optical Instrumentation ZJU-Hangzhou Global Scientific and Technological Innovation Center Zhejiang University Hangzhou 310027 P. R. China Air and Missile Defend College Air Force Engineering University Xi'an 710051 P. R. China International Joint Innovation Center Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang The Electromagnetics Academy at Zhejiang University Zhejiang University Haining 314400 P. R. China Department of Physics Faculty of Science Ningbo University Ningbo 315211 P. R. China

Invisibility has been a topic of long-standing interest owing to the advent of metamaterials and transformation optics, but still faces open challenges after its tremendous development in recent decades. One of the big challenges is the narrow bandwidth, as the realization of an invisibility cloak is usually based on a metamaterial—an artificial composite material composed of subwavelength resonator structures that are always associated with dispersion. Different from previous works that have tried to eliminate the material dispersion to enhance the bandwidth of an invisibility cloak, here, it is found that by judiciously harnessing the material dispersion, the bandwidth of the cloak can still be significantly increased. Interestingly, the material dispersion does not violate the law of causality. As a proof of concept, an ultrabroadband terahertz (THz) carpet cloak is experimentally demonstrated through an array of superdispersive microparticles, rendering the target object invisible to detection by both time- and frequency-domain wideband systems. The work presents a feasible invisibility strategy that is closer to practical applications and may pave a brand-new way for the development of dispersion-dominated ultrabroadband metadevices.

关键词： invisibility cloaks metasurfaces superdispersive microparticles ultra-broadband