Perfect anomalous reflections have been demonstrated in optical phase gradient metasurfaces(PGMs),but they suffer from single-frequency(narrow-band)response due to the intrinsic limitation of natural geometric periodi...Perfect anomalous reflections have been demonstrated in optical phase gradient metasurfaces(PGMs),but they suffer from single-frequency(narrow-band)response due to the intrinsic limitation of natural geometric periodicity.Here,we provide both numerical and analytical evidence that a depth gradient metasurface can achieve discrete ultra-broadband perfect anomalous reflection in the microwave range in the absence of geometric periodicity.Remarkably,by adjusting the operating frequency of the incident wave,the same effect can be steadily obtained via a physically equivalent phase periodicity in the PGM.Based on this mechanism,a perfect retroreflector with a broadband response ranging from 1 GHz to 40 GHz is realized.Our work has promising applications in communication,source tracking,and military satellites.展开更多
The finding of Snell’s law for anomalous reflection enables broad applications of metasurfaces in stealth,communication,radar technology,etc.However,some unavoidable high-order modes are inherently generated due to t...The finding of Snell’s law for anomalous reflection enables broad applications of metasurfaces in stealth,communication,radar technology,etc.However,some unavoidable high-order modes are inherently generated due to the super lattice of this local approach,which thus causes a decrease in efficiency and a limit in the reflected angle.Here,a novel,to our knowledge,low-profile wideband reflective meta-atom shaped like a four-leaf rose is proposed to achieve a phase coverage of full 360°by varying the length of the rose leaf.Then,the genetic algorithm is adopted for the first time to encode and optimize the topology of each meta-atom on the coding metasurface to achieve two-dimensional(2D)anomalous reflection with excellent performances through an inverse design.Numerical results show that our optimized coding metasurfaces achieve a high-efficiency(≥90%)and large-angle(θ≤70°and 0°≤φ≤360°)reflection under normal incidence.For verification,far-field measurement is carried out and experimental results are consistent with the numerical ones.Our work sets up a solid platform for utilizing algorithms,especially in artificial intelligence,in the future for arbitrary 2D anomalous reflection with high efficiency and a large angle.展开更多
Nano-kirigami technology enables the flexible transformation of two-dimensional(2D)micro/nanoscale structures into three-dimensional(3D)structures with either open-loop or close-loop topological morphologies,and has a...Nano-kirigami technology enables the flexible transformation of two-dimensional(2D)micro/nanoscale structures into three-dimensional(3D)structures with either open-loop or close-loop topological morphologies,and has aroused significant interest in the fields of nanophotonics and optoelectronics.Here,we propose an innovative kissing-loop nano-kirigami strategy,wherein 2D open-loop structures can transform into 3D kissing-loop structures while retaining advantages such as large deformation heights and multiple optical modulations.Benefited from the unidirectional deformation of the structures,the kissing-loop nano-kirigami exhibits significant asymmetric transmission under x-polarized light incidence.Importantly,the Pancharatnam-Berry geometric phase is experimentally realized in nano-kirigami structures for the first time,resulting in broadband anomalous reflection in the near-infrared wavelength region.The kissing-loop nano-kirigami strategy can expand the existing platform of micro/nanoscale fabrication and provide an effective method for developing optical sensing,spatial light modulations,and optoelectronic devices.展开更多
The reflection of X-band microwaves （8-12 GHz） from a metallic aluminum （A1） surface with groove grating corrugations was investigated experimentally. It was shown that the reflection of p-polarization is much les...The reflection of X-band microwaves （8-12 GHz） from a metallic aluminum （A1） surface with groove grating corrugations was investigated experimentally. It was shown that the reflection of p-polarization is much less than the microwave reflected from the corresponding area of an unruled Al surface, with selective wavelength. The experimental results demonstrated that the anomalous microwave reflection is strongly associated with the excitation of spoof surface plasmons at the Al air interface by the surface grating coupler. This near-total absence of reflected microwaves is similar to the famous Wood＇s anomaly in the optical regime and is of fundamental importance to the applications of spoof surface plasmons in the microwave regime.展开更多
An ultra-thin metasurface is proposed to realize wideband polarization-independent anomalous reflection. The sub-wavelengthresonator can produce different resonance modes, which are the result of the combined effect o...An ultra-thin metasurface is proposed to realize wideband polarization-independent anomalous reflection. The sub-wavelengthresonator can produce different resonance modes, which are the result of the combined effect of dielectric and the metallic structure.The gradient metasurface is done by six discrete orientation of the local sub-wavelength resonator which provides a phase gradient.The simulation and measured results show that 9 GHz bandwidth of the anomalous reflection is achieved.展开更多
Abnormal refraction and reflection refers to the phenomenon in which light does not follow its traditional laws of propagation and instead is subject to refraction and reflection at abnormal angles that satisfy a gene...Abnormal refraction and reflection refers to the phenomenon in which light does not follow its traditional laws of propagation and instead is subject to refraction and reflection at abnormal angles that satisfy a generalization of Snell’s law.Metasurfaces can realize this phenomenon through appropriate selection of materials and structural design,and they have a wide range of potential applications in the military,communications,scientific,and biomedical fields.This paper summarizes the current state of research on abnormal refractive and reflective metasurfaces and their application scenarios.It discusses types of abnormal refractive and reflective metasurfaces based on their tuning modes(active and passive),their applications in different wavelength bands,and their future development.The technical obstacles that arise with existing metasurface technology are summarized,and prospects for future development and applications of abnormal refractive and reflective metasurfaces are discussed.展开更多
Acoustic metasurface has attracted increasing attention due to the ability of manipulating the transmitted and reflected phase of waves to generate various acoustic functionalities with planar layer of sub-wavelength ...Acoustic metasurface has attracted increasing attention due to the ability of manipulating the transmitted and reflected phase of waves to generate various acoustic functionalities with planar layer of sub-wavelength structure.We design an acoustic metasurface with a semi-closed and nested slotted tube array,and it possesses the capacity of modulating the reflected phase with sub-wavelength thickness (about λ/23).The reflected phase shifts can be obtained from 0 to 2π by different rotation angles of internal slotted tubes.The theoretical results agree well with the numerical results by a finite element method.The results show that some excellent wavefront manipulations are demonstrated with the phase array by using acoustic metasurface such as anomalous reflection and sub-wavelength flat focusing.The design may offer a path for acoustic manipulation and promote the potential applications of acoustic metasurface in low frequency noise control,acoustic imaging and cloaking.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12274313,62275184,and 62411540033)Collaborative Innovation Center of Suzhou Nano Science and Technology,Suzhou Basic Research Project(Grant No.SJC2023003)+1 种基金the Gusu Leading Talent Plan for Scientific and Technological Innovation and Entrepreneurship(Grant No.ZXL2024400)the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Perfect anomalous reflections have been demonstrated in optical phase gradient metasurfaces(PGMs),but they suffer from single-frequency(narrow-band)response due to the intrinsic limitation of natural geometric periodicity.Here,we provide both numerical and analytical evidence that a depth gradient metasurface can achieve discrete ultra-broadband perfect anomalous reflection in the microwave range in the absence of geometric periodicity.Remarkably,by adjusting the operating frequency of the incident wave,the same effect can be steadily obtained via a physically equivalent phase periodicity in the PGM.Based on this mechanism,a perfect retroreflector with a broadband response ranging from 1 GHz to 40 GHz is realized.Our work has promising applications in communication,source tracking,and military satellites.
基金National Natural Science Foundation of China(62171459)Innovative Talents Cultivate Program for Technology Innovation Team of Shaanxi Province(2024RSCXTD-08)Key Research and Development Program of Shaanxi Province(2022GD-TSLD-64)。
文摘The finding of Snell’s law for anomalous reflection enables broad applications of metasurfaces in stealth,communication,radar technology,etc.However,some unavoidable high-order modes are inherently generated due to the super lattice of this local approach,which thus causes a decrease in efficiency and a limit in the reflected angle.Here,a novel,to our knowledge,low-profile wideband reflective meta-atom shaped like a four-leaf rose is proposed to achieve a phase coverage of full 360°by varying the length of the rose leaf.Then,the genetic algorithm is adopted for the first time to encode and optimize the topology of each meta-atom on the coding metasurface to achieve two-dimensional(2D)anomalous reflection with excellent performances through an inverse design.Numerical results show that our optimized coding metasurfaces achieve a high-efficiency(≥90%)and large-angle(θ≤70°and 0°≤φ≤360°)reflection under normal incidence.For verification,far-field measurement is carried out and experimental results are consistent with the numerical ones.Our work sets up a solid platform for utilizing algorithms,especially in artificial intelligence,in the future for arbitrary 2D anomalous reflection with high efficiency and a large angle.
基金supported by the National Natural Science Foundation of China(Grant No.T2325005,62375016)Science and Technology Project of Guangdong(2020B010190001).
文摘Nano-kirigami technology enables the flexible transformation of two-dimensional(2D)micro/nanoscale structures into three-dimensional(3D)structures with either open-loop or close-loop topological morphologies,and has aroused significant interest in the fields of nanophotonics and optoelectronics.Here,we propose an innovative kissing-loop nano-kirigami strategy,wherein 2D open-loop structures can transform into 3D kissing-loop structures while retaining advantages such as large deformation heights and multiple optical modulations.Benefited from the unidirectional deformation of the structures,the kissing-loop nano-kirigami exhibits significant asymmetric transmission under x-polarized light incidence.Importantly,the Pancharatnam-Berry geometric phase is experimentally realized in nano-kirigami structures for the first time,resulting in broadband anomalous reflection in the near-infrared wavelength region.The kissing-loop nano-kirigami strategy can expand the existing platform of micro/nanoscale fabrication and provide an effective method for developing optical sensing,spatial light modulations,and optoelectronic devices.
基金Project supported by the National Basic Research Program of China(Grant No.2008CB717800)the Doctoral Program o fMinistry of Education of China(Grant No.20093402110027)
文摘The reflection of X-band microwaves （8-12 GHz） from a metallic aluminum （A1） surface with groove grating corrugations was investigated experimentally. It was shown that the reflection of p-polarization is much less than the microwave reflected from the corresponding area of an unruled Al surface, with selective wavelength. The experimental results demonstrated that the anomalous microwave reflection is strongly associated with the excitation of spoof surface plasmons at the Al air interface by the surface grating coupler. This near-total absence of reflected microwaves is similar to the famous Wood＇s anomaly in the optical regime and is of fundamental importance to the applications of spoof surface plasmons in the microwave regime.
文摘An ultra-thin metasurface is proposed to realize wideband polarization-independent anomalous reflection. The sub-wavelengthresonator can produce different resonance modes, which are the result of the combined effect of dielectric and the metallic structure.The gradient metasurface is done by six discrete orientation of the local sub-wavelength resonator which provides a phase gradient.The simulation and measured results show that 9 GHz bandwidth of the anomalous reflection is achieved.
基金This work was supported by the Chinese Academy of Sciences Strategic Pioneering Science and Technology Special Project(XDA28050200)the Jilin Province Science and Technology Development Program in China(20200403062SF,20200401141GX,20210201023GX,20210201140GX,and 20210203059SF)+1 种基金the Chinese Academy of Sciences Research Instrumentation Development Project(YJKYYQ20200048)the Science and Technology Innovation Platform of Jilin Province(20210502016ZP).
文摘Abnormal refraction and reflection refers to the phenomenon in which light does not follow its traditional laws of propagation and instead is subject to refraction and reflection at abnormal angles that satisfy a generalization of Snell’s law.Metasurfaces can realize this phenomenon through appropriate selection of materials and structural design,and they have a wide range of potential applications in the military,communications,scientific,and biomedical fields.This paper summarizes the current state of research on abnormal refractive and reflective metasurfaces and their application scenarios.It discusses types of abnormal refractive and reflective metasurfaces based on their tuning modes(active and passive),their applications in different wavelength bands,and their future development.The technical obstacles that arise with existing metasurface technology are summarized,and prospects for future development and applications of abnormal refractive and reflective metasurfaces are discussed.
基金supported by the National Natural Science Foundation of China (No.51575431)the China Postdoctoral Science Foundation Funded Project (Nos. 2014M550485, 2015T81019)+1 种基金the Fundamental Research Funds for the Central Universities (No.xjj2015098)the Shaanxi Province Postdoctoral Science Foundation Funded Project
文摘Acoustic metasurface has attracted increasing attention due to the ability of manipulating the transmitted and reflected phase of waves to generate various acoustic functionalities with planar layer of sub-wavelength structure.We design an acoustic metasurface with a semi-closed and nested slotted tube array,and it possesses the capacity of modulating the reflected phase with sub-wavelength thickness (about λ/23).The reflected phase shifts can be obtained from 0 to 2π by different rotation angles of internal slotted tubes.The theoretical results agree well with the numerical results by a finite element method.The results show that some excellent wavefront manipulations are demonstrated with the phase array by using acoustic metasurface such as anomalous reflection and sub-wavelength flat focusing.The design may offer a path for acoustic manipulation and promote the potential applications of acoustic metasurface in low frequency noise control,acoustic imaging and cloaking.
