检索结果-内蒙古大学图书馆

Optical interface engineering with on-demand magnetic surface conductivities

Physical Review B 2022年第3期106卷 035304-035304页

作者： Yuhan Zhong Tong Cai Tony Low Hongsheng Chen Xiao Lin Interdisciplinary Center for Quantum Information State Key Laboratory of Modern Optical Instrumentation ZJU-Hangzhou Global Scientific and Technological Innovation Center College of Information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China International Joint Innovation Center ZJU-UIUC Institute Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang The Electromagnetics Academy at Zhejiang University Zhejiang University Haining 314400 China Department of Electrical and Computer Engineering University of Minnesota Minneapolis Minnesota 55455 USA

Optical interfaces with arbitrary magnetic and electric surface conductivities can enable the design of photonic devices with new functionalities, but practical approaches to date are nonexistent. Regular interfaces, such as those with graphene, are optically interesting due to their tailorable electric surface conductivity. However, their magnetic surface conductivity is negligible since the magnetic response in natural materials is generally weak from the terahertz frequency onward. The quest for artificial magnetic response has recently triggered the development of magnetic metasurfaces that, however, can only provide the interface with a limited value of magnetic surface conductivity. Herein we find that vertical heterostructures based on regular nonmagnetic metasurfaces have a direct correspondence to an optical interface with both magnetic and electric surface conductivities, whose desired values can be structurally engineered. Moreover, we identify several unique photonic and plasmonic responses at optical interfaces with specific magnetic surface conductivities, including a polarization-insensitive Brewster effect and pure magnetic surface waves.

关键词： Electrical conductivity Electromagnetism Surface & interfacial phenomena Surface plasmons

来源：评论

学校读者我要写书评

暂无评论

Non-Hermitian scattering symmetry revealed by diffusive channels

arXiv

引用

arXiv 2023年

作者： Wang, Dong Chen, Hongsheng Qiu, Cheng-Wei Li, Ying 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 Jinhua Institute of Zhejiang University Zhejiang University Jinhua321099 China Department of Electrical and Computer Engineering National University of Singapore Singapore117583 Singapore

The Hamiltonian interprets how the system evolves, while the scattering coefficients describe how the system responds to inputs. Recent studies on non-Hermitian physics have revealed many unconventional effects. However, in all cases, the non-Hermiticity such as material loss is only considered for the Hamiltonian, even when studying scattering properties. Another important component-the scattering channel, is always assumed to be lossless and time-reversal symmetric. This assumption hinders the exploration on the more general and fundamental properties of non-Hermitian scattering. Here, we identify a novel kind of scattering channel that obeys time-reversal anti-symmetry. Such diffusive scattering channels overturn the conventional understanding about scattering symmetry by linking the positive and negative frequencies. By probing non-Hermitian systems with the diffusive channels, we reveal a hidden anti-parity-time (APT) scattering symmetry, which is distinct from the APT symmetry of Hamiltonians studied before. The symmetric and symmetry broken scattering phases are observed for the first time as the collapse and revival of temperature oscillation. Our work highlights the overlooked role of scattering channels in the symmetry and phase transition of non-Hermitian systems, thereby gives the diffusion the new life as a signal carrier. Our findings can be utilized to the analysis and control of strongly dissipative phenomena such as heat transfer and charge diffusion. © 2023, CC BY.

关键词： Hamiltonians

来源：评论

学校读者我要写书评

暂无评论

Non-Hermitian Chiral Heat Transport

引用

Physical Review Letters 2023年第26期130卷 266303-266303页

作者： Guoqiang Xu Xue Zhou Ying Li Qitao Cao Weijin Chen Yunfeng Xiao Lan Yang Cheng-Wei Qiu Department of Electrical and Computer Engineering National University of Singapore Kent Ridge 117583 Republic of Singapore School of Computer Science and Information Engineering Chongqing Technology and Business University Chongqing 400067 China 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 Key Lab of Advanced Micro/Nano Electronic Devices and Smart Systems of Zhejiang The Electromagnetics Academy at Zhejiang University Zhejiang University Haining 314400 China State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics School of Physics Peking University100871 Beijing China Department of Electrical and Systems Engineering Washington University St. Louis Missouri 63130 USA

Exceptional point (EP) has been captivated as a concept of interpreting eigenvalue degeneracy and eigenstate exchange in non-Hermitian physics. The chirality in the vicinity of EP is intrinsically preserved and usually immune to external bias or perturbation, resulting in the robustness of asymmetric backscattering and directional emission in classical wave fields. Despite recent progress in non-Hermitian thermal diffusion, all state-of-the-art approaches fail to exhibit chiral states or directional robustness in heat transport. Here we report the first discovery of chiral heat transport, which is manifested only in the vicinity of EP but suppressed at the EP of a thermal system. The chiral heat transport demonstrates significant robustness against drastically varying advections and thermal perturbations imposed. Our results reveal the chirality in heat transport process and provide a novel strategy for manipulating mass, charge, and diffusive light.

关键词： Diffusion Heat transfer Metamaterials Non-Hermitean systems

来源：评论

学校读者我要写书评

暂无评论

Ultrafast control of braiding topology in non-Hermitian metasurfaces

arXiv

引用

arXiv 2024年

作者： Hu, Yuze Tong, Mingyu Ren, Ziheng Chen, Fujia Chen, Qiaolu Chen, Hongsheng Jiang, Tian 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 Hangzhou310027 China Institute for Quantum Science and Technology College of Science National University of Defense Technology Changsha410073 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 of Zhejiang University Zhejiang University Jinhua321099 China Shaoxing Institute of Zhejiang University Zhejiang University Shaoxing312000 China College of Advanced Interdisciplinary Studies National University of Defense Technology Changsha410073 China

The mathematical theory of braids, influential across scientific disciplines, has emerged as a compelling strategy for light manipulation. Existing approaches to creating braids in photonics, whether in momentum-space bandstructures or real-space fields, often face limitations associated with static nature of devices and lack of tunability. Here, we experimentally demonstrate ultrafast control of eigen-spectrum braids of Jones matrices within mere picoseconds, in reconfigurable non-Hermitian metasurfaces. The Jones matrices of the metasurface exhibit a complex eigen-spectrum that braids in the three-dimensional eigenvalue-frequency space, thereby creating arbitrary elements within the two-string braid group, 2. By exciting the photoconductive semiconductor terahertz metasurface with a femtosecond infrared pulse, we achieve ultrafast switching of the braids, transitioning from the Solomon link to either the Trefoil knot or Hopf link. Our approach serves as a pivotal tool for elucidating non-trivial topology of braids and studying ultrafast topological optoelectronics. © 2024, CC BY.

关键词： Topology

来源：评论

学校读者我要写书评

暂无评论

Scattering-free plasmonic Brewster effect via metasurfaces

arXiv

引用

arXiv 2024年

作者： Zhang, Xinyan Cui, Xingshuo Cai, Tong Cai, Weiqi Low, Tony Chen, Hongsheng Lin, Xiao Interdisciplinary Center for Quantum Information State Key Laboratory of Extreme Photonics and Instrumentation College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China International Joint Innovation Center The Electromagnetics Academy at Zhejiang University Zhejiang University Haining314400 China Air and Missile Defense College Air Force Engineering University Xi’an710051 China AVIC Research Institute for Special Structures of Aeronautical Composites Jinan250023 China Department of Electrical and Computer Engineering University of Minnesota MinneapolisMN55455 United States 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

The Brewster effect, dating back to the pioneering work of Sir David Brewster in 1815, offers a crucial route to achieve 100% energy conversion between the incident and transmitted propagating waves at an optical interface and is of fundamental importance to many practical applications, such as polarization filtering, beam steering, and optical broadband angular selectivity. However, whether the Brewster effect of surface waves can be implemented without the involvement of negative-permittivity or negative-permeability materials remains elusive. This is due to the formidable challenge to fully suppress both the parasitic scattering into propagating waves and the reflection into surface waves under the incidence of surface waves. Here, we reveal a feasible route to achieve scattering-free plasmonic Brewster effect via isotropic metasurfaces, along with the usage of positive-permittivity and positive-permeability metamaterials with both anisotropic and magnetic responses. In essence, the anisotropic response of metamaterials is judiciously designed to fully suppress the parasitic scattering into propagating waves, while the magnetic response of metamaterials facilitates the full suppression of the reflection into surface waves supported by metasurfaces. Moreover, we find that this plasmonic Brewster effect via metasurfaces can be further engineered to occur for arbitrary incident angles, giving rise to the exotic phenomenon of all-angle scattering-free plasmonic Brewster effect. © 2024, CC BY.

关键词： Surface waves

来源：评论

学校读者我要写书评

暂无评论

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

arXiv

引用

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

来源：评论

学校读者我要写书评

暂无评论

Multiple Brillouin Zone Winding of Topological Chiral Edge States for Slow Light Applications

引用

Physical Review Letters 2024年第15期132卷 156602-156602页

作者： Fujia Chen Haoran Xue Yuang Pan Maoren Wang Yuanhang Hu Li Zhang Qiaolu Chen Song Han Gui-geng Liu Zhen Gao Peiheng Zhou Wenyan Yin Hongsheng Chen Baile Zhang Yihao Yang 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 Department of Physics The Chinese University of Hong Kong Shatin Hong Kong SAR China Key Laboratory of Multi-spectral Absorbing Materials and Structures of Ministry of Education University of Electronic Science and Technology of China Chengdu 611731 China Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link Singapore 637371 Singapore Centre for Disruptive Photonic Technologies The Photonics Institute Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore Department of Electrical and Electronic Engineering Southern University of Science and Technology Shenzhen 518055 China

Photonic Chern insulators are known for their topological chiral edge states (CESs), whose absolute existence is determined by the bulk band topology, but concrete dispersion can be engineered to exhibit various properties. For example, the previous theory suggested that the edge dispersion can wind many times around the Brillouin zone to slow down light, which can potentially overcome fundamental limitations in conventional slow-light devices: narrow bandwidth and keen sensitivity to fabrication imperfection. Here, we report the first experimental demonstration of this idea, achieved by coupling CESs with resonance-induced nearly flat bands. We show that the backscattering-immune hybridized CESs are significantly slowed down over a relatively broad bandwidth. Our work thus paves an avenue to broadband topological slow-light devices.

关键词： Light propagation, transmission & absorption Metamaterials Photonic crystals Polaritons Topological materials

来源：评论

学校读者我要写书评

暂无评论

Type-II Dirac points and topological Fermi arcs in nonlocal metamaterials

引用

Physical Review B 2022年第23期106卷 235303-235303页

作者： Mingzhu Li Ning Han Liang Peng Shuang Zhang School of Information and Electrical Engineering Zhejiang University City College Hangzhou 310015 China Interdisciplinary Center for Quantum Information State Key Laboratory of Modern Optical Instrumentation College of Information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China ZJU-Hangzhou Global Science and Technology Innovation Center Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang ZJU-UIUC Institute Zhejiang University Hangzhou 310027 China Department of Physics University of Hong Kong Hong Kong China Department of Electrical & Electronic Engineering University of Hong Kong Hong Kong China

Dirac semimetals are topological materials with degenerated Dirac points in their band structures. In particular, the Dirac points play a central role in the topologically protected phases. Recently, it was reported that the peculiar type-II Dirac points could be realized in photonics by means of photonic crystals (PCs). Nevertheless, the practical implementation is rather challenging. In this paper, we demonstrate that the nonlocal effect in the interior of a homogeneous photonic metamaterial (HPM) enables the existence of type-II Dirac points in the HPM's band structure. With theoretical formulations and numerical evaluations, we discuss the evolution of the HPM's band type and present the interesting transition between type-I and type-II Dirac degeneracy of the HPMs. Remarkably, a pair of the type-II Dirac points can be generated at two different frequencies, which is supported by the mode overlapping in the HPMs with weak nonlocality. The Fermi arc surface states connect the projections of the type-II Dirac points at the boundary between the vacuum and HPMs. The topological protection of the Fermi arc surface states is verified by the reflectionless transmission with sharp corners. Our paper provides a fundamental understanding of topological photonics by type-II Dirac points in HPMs.

关键词： Surface states Topological phases of matter Dirac semimetal Topological materials

来源：评论

学校读者我要写书评

暂无评论

Polarization-Orthogonal Nondegenerate Plasmonic Higher-Order Topological States

引用

Physical Review Letters 2023年第21期130卷 213603-213603页

作者： Yuanzhen Li Su Xu Zijian Zhang Yumeng Yang Xinrong Xie Wenzheng Ye Feng Liu Haoran Xue Liqiao Jing Zuojia Wang Qi-Dai Chen Hong-Bo Sun Erping Li Hongsheng Chen Fei Gao 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 Laboratory of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang Jinhua Institute of Zhejiang University Zhejiang University Jinhua 321099 China State Key Laboratory of Integrated Optoelectronics College of Electronic Science and Engineering Jilin University 2699 Qianjin Street Changchun 130012 China Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision Instrument Tsinghua University Haidian Beijing 100084 China Shaoxing Institute of Zhejiang University Zhejiang University Shaoxing 312000 China

Photonic topological states, providing light-manipulation approaches in robust manners, have attracted intense attention. Connecting photonic topological states with far-field degrees of freedom (d.o.f.) has given rise to fruitful phenomena. Recently emerged higher-order topological insulators (HOTIs), hosting boundary states two or more dimensions lower than those of bulk, offer new paradigms to localize or transport light topologically in extended dimensionalities. However, photonic HOTIs have not been related to d.o.f. of radiation fields yet. Here, we report the observation of polarization-orthogonal second-order topological corner states at different frequencies on a designer-plasmonic kagome metasurface in the far field. Such phenomenon stands on two mechanisms, i.e., projecting the far-field polarizations to the intrinsic parity d.o.f. of lattice modes and the parity splitting of the plasmonic corner states in spectra. We theoretically and numerically show that the parity splitting originates from the underlying interorbital coupling. Both near-field and far-field experiments verify the polarization-orthogonal nondegenerate second-order topological corner states. These results promise applications in robust optical single photon emitters and multiplexed photonic devices.

关键词： Metasurfaces Topological effects in photonic systems

来源：评论

学校读者我要写书评

暂无评论

Observation of Multiple Topological Corner States in Thermal Diffusion

arXiv

引用

arXiv 2023年

作者： Qi, Minghong Wang, Yanxiang Cao, Pei-Chao Zhu, Xue-Feng Gao, Fei Chen, Hongsheng Li, Ying 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 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 of Zhejiang University Zhejiang University Jinhua321099 China Shaoxing Institute of Zhejiang University Zhejiang University Shaoxing312000 China School of Physics Innovation Institute Huazhong University of Science and Technology Wuhan430074 China

Higher-dimensional topological meta-materials have more flexible than one-dimensional topological materials, which are more convenient to apply and solve practical problems. However, in diffusion systems, higher-dimensional topological states have not been well studied. In this work, we experimentally realized the 2D topological structure based on a kagome lattice of thermal metamaterial. Due to the anti-Hermitian properties of the diffusion Hamiltonian, it has purely imaginary eigenvalues corresponding to the decay rate. By theoretical analysis and directly observing the decay rate of temperature through experiments, we present the various corner states in 2D topological diffusive system. Our work constitutes the first realization of multiple corner states with high decay rates in a pure diffusion system, which provides a new idea for the design of topological protected thermal metamaterial in the future. © 2023, CC BY.

关键词： Metamaterials

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：