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| 1 | Coding metamaterials, digital metamaterials and programmable metamaterials显示文摘Metamaterials are artificial structures that are usually described by effective medium parameters on the macroscopic scale,and these metamaterials are referred to as‘analog metamaterials’.Here,we propose‘digital metamaterials’through two steps.First,we present‘coding metamaterials’that are composed of only two types of unit cells,with 0 and p phase responses,which we name‘0’and‘1’elements,respectively.By coding‘0’and‘1’elements with controlled sequences(i.e.,1-bit coding),we can manipulate electromagnetic(EM)waves and realize different functionalities.The concept of coding metamaterials can be extended from 1-bit coding to 2-bit coding or higher.In 2-bit coding,four types of unit cells,with phase responses of 0,p/2,p,and 3p/2,are required to mimic the‘00’,‘01’,‘10’and‘11’elements,respectively.The 2-bit coding has greater freedom than 1-bit coding for controlling EM waves.Second,we propose a unique metamaterial particle that has either a‘0’or‘1’response controlled by a biased diode.Based on this particle,we present‘digital metamaterials’with unit cells that possess either a‘0’or‘1’state.Using a field-programmable gate array,we realize digital control over the digital metamaterial.By programming different coding sequences,a single digital metamaterial has the ability to manipulate EM waves in different manners,thereby realizing‘programmable metamaterials’.The above concepts and physical phenomena are confirmed through numerical simulations and experiments using metasurfaces. | Tie Jun Cui Mei Qing Qi Xiang Wan Jie Zhao Qiang Cheng | 2014 | Light(Science & Applications)2014,3,1: | 130 |
| 2 | Programmable time-domain digital-coding metasurface for non-linear harmonic manipulation and new wireless communication systems显示文摘Optical non-linear phenomena are typically observed in natural materials interacting with light at high intensities, and they benefit a diverse range of applications from communication to sensing. However,controlling harmonic conversion with high efficiency and flexibility remains a major issue in modern optical and radio-frequency systems. Here, we introduce a dynamic time-domain digital-coding metasurface that enables efficient manipulation of spectral harmonic distribution. By dynamically modulating the local phase of the surface reflectivity, we achieve accurate control of different harmonics in a highly programmable and dynamic fashion, enabling unusual responses, such as velocity illusion. As a relevant application, we propose and realize a novel architecture for wireless communication systems based on the time-domain digital-coding metasurface, which largely simplifies the architecture of modern communication systems, at the same time yielding excellent performance for real-time signal transmission. The presented work, from new concept to new system, opens new pathways in the application of metamaterials to practical technology. | Jie Zhao Xi Yang Jun Yan Dai Qiang Cheng Xiang Li Ning Hua Qi Jun Chen Ke Guo Dong Bai Shuo Liu Shi Jin Andrea Alù Tie Jun Cui | 2019 | National Science Review2019,6,2: | 46 |
| 3 | Anisotropic coding metamaterials and their powerful manipulation of differently polarized terahertz waves显示文摘Metamaterials based on effective media can be used to produce a number of unusual physical properties(for example,negative refraction and invisibility cloaking)because they can be tailored with effective medium parameters that do not occur in nature.Recently,the use of coding metamaterials has been suggested for the control of electromagnetic waves through the design of coding sequences using digital elements‘0’and‘1,'which possess opposite phase responses.Here we propose the concept of an anisotropic coding metamaterial in which the coding behaviors in different directions are dependent on the polarization status of the electromagnetic waves.We experimentally demonstrate an ultrathin and flexible polarization-controlled anisotropic coding metasurface that functions in the terahertz regime using specially designed coding elements.By encoding the elements with elaborately designed coding sequences(both 1-bit and 2-bit sequences),the x-and y-polarized waves can be anomalously reflected or independently diffused in three dimensions.The simulated far-field scattering patterns and near-field distributions are presented to illustrate the dual-functional performance of the encoded metasurface,and the results are consistent with the measured results.We further demonstrate the ability of the anisotropic coding metasurfaces to generate a beam splitter and realize simultaneous anomalous reflections and polarization conversions,thus providing powerful control of differently polarized electromagnetic waves.The proposed method enables versatile beam behaviors under orthogonal polarizations using a single metasurface and has the potential for use in the development of interesting terahertz devices. | Shuo Liu Tie Jun Cui Quan Xu Di Bao Liangliang Du Xiang Wan Wen Xuan Tang Chunmei Ouyang Xiao Yang Zhou Hao Yuan Hui Feng Ma Wei Xiang Jiang Jiaguang Han Weili Zhang Qiang Cheng | 2016 | Light(Science & Applications)2016,5,1: | 36 |
| 4 | Independent control of harmonic amplitudes and phases via a time-domain digital coding metasurface显示文摘Harmonic manipulations are important for applications such as wireless communications,radar detection and biological monitoring.A general approach to tailor the harmonics involves the use of additional amplifiers and phase shifters for the precise control of harmonic amplitudes and phases after the mixing process;however,this approach leads to issues of high cost and system integration.Metasurfaces composed of a periodic array of subwavelength resonators provide additional degrees of freedom to realize customized responses to incident light and highlight the possibility for nonlinear control by taking advantage of time-domain properties.Here,we designed and experimentally characterized a reflective time-domain digital coding metasurface,with independent control of the harmonic amplitude and phase.As the reflection coefficient is dynamically modulated in a predefined way,a large conversion rate is observed from the carrier signal to the harmonic components,with magnitudes and phases that can be accurately and separately engineered.In addition,by encoding the reflection phases of the meta-atoms,beam scanning for multiple harmonics can be implemented via different digital coding sequences,thus removing the need for intricate phase-shift networks.This work paves the way for efficient harmonic control for applications in communications,radar,and related areas. | Jun Yan Dai Jie Zhao Qiang Cheng Tie Jun Cui | 2018 | Light(Science & Applications)2018,7,1: | 29 |
| 5 | Wireless Communications with Programmable Metasurface:Transceiver Design and Experimental Results显示文摘Metasurfaces have drawn significant attentions due to their superior capability in tailoring electromagnetic waves with a wide frequency range, from microwave to visible light. Recently, programmable metasurfaces have demonstrated the ability of manipulating the amplitude or phase of electromagnetic waves in a programmable manner in real time, which renders them especially appealing in the applications of wireless communications. In this paper, we present the fundamental principle of applying programmable metasurface as transmitter for wireless communications. Then, we establish a prototype system of metasurface-based transmitter to conduct several experiments and measurements over the air, which practically demonstrate the feasibility of using programmable metasurfaces in future communication systems. By exploiting the dynamically controllable property of programmable metasurface, the design, implementation and experimental evaluation of the proposed metasurface-based wireless communication system are presented with the prototype, which realizes single carrier quadrature phase shift keying(QPSK) transmission over the air. In the developed prototype, the phase of the reflected electromagnetic wave of programma-ble metasurface is directly manipulated in real time according to the baseband control signal, which achieves 2.048 Mbps data transfer rate with video streaming transmission over the air. In addition, experimental result is provided to compare the performance of the proposed metasurface-based architecture against the conventional one. With the slight increase of the transmit power by 5 dB, the same bit error rate(BER) performance can be achieved as the conventional system in the absence of channel coding. Such a result is encouraging considering that the metasurface-based system has the advantages of low hardware cost and simple structure, thus leading to a promising new architecture for wireless communications. | Wankai Tang Xiang Li Jun Yan Dai Shi Jin Yong Zeng Qiang Cheng Tie Jun Cui | 2019 | China Communications2019,16,5: | 23 |
| 6 | Direct Transmission of Digital Message via Programmable Coding Metasurface显示文摘In modern wireless communications,digital information is frstly converted to analog signal by a digital-analog convertor,which is then mixed to high-frequency microwave to be transmitted through a series of devices including modulator,mixer,amplifer,flter,and antenna and is fnally received by terminals via a reversed process.Although the wireless communication systems have evolved signifcantly over the past thirty years,the basic architecture has not been challenged.Here,we propose a method to transmit digital information directly via programmable coding metasurface.Since the coding metasurface is composed of‘0’and‘1’digital units with opposite phase responses,the digital information can be directly modulated to the metasurface with certain coding sequences and sent to space under the illumination of feeding antenna.Te information,being modulated in radiation patterns of the metasurface,can be correctly received by multiple receivers distributed in diferent locations.Tis method provides a completely new architecture for wireless communications without using complicated digital-analog convertor and a series of active/passive microwave devices.We build up a prototype to validate the new architecture experimentally,which may fnd promising applications where information security is highly demanded. | Tie Jun Cui Shuo Liu Guo Dong Bai Qian Ma | 2019 | Research2019,,1: | 20 |
| 7 | Smart metasurface with self-adaptively reprogrammable functions显示文摘Intelligence at either the material or metamaterial level is a goal that researchers have been pursuing.From passive to active,metasurfaces have been developed to be programmable to dynamically and arbitrarily manipulate electromagnetic(EM)wavefields.However,the programmable metasurfaces require manual control to switch among different functionalities.Here,we put forth a smart metasurface that has self-adaptively reprogrammable functionalities without human participation.The smart metasurface is capable of sensing ambient environments by integrating an additional sensor(s)and can adaptively adjust its EM operational functionality through an unmanned sensing feedback system.As an illustrative example,we experimentally develop a motion-sensitive smart metasurface integrated with a three-axis gyroscope,which can adjust self-adaptively the EM radiation beams via different rotations of the metasurface.We develop an online feedback algorithm as the control software to make the smart metasurface achieve single-beam and multibeam steering and other dynamic reactions adaptively.The proposed metasurface is extendable to other physical sensors to detect the humidity,temperature,illuminating light,and so on.Our strategy will open up a new avenue for future unmanned devices that are consistent with the ambient environment. | Qian Ma Guo Dong Bai Hong Bo Jing Cheng Yang Lianlin Li Tie Jun Cui | 2019 | Light(Science & Applications)2019,8,1: | 13 |
| 8 | Accurate and broadband manipulations of harmonic amplitudes and phases to reach 256 QAM millimeter-wave wireless communications by time-domain digital coding metasurface显示文摘We propose a theoretical mechanism and new coding strategy to realize extremely accurate manipulations of nonlinear electromagnetic harmonics in ultrawide frequency band based on a time-domain digital coding metasurface(TDCM).Using the proposed mechanism and coding strategy,we design and fabricate a millimeter-wave(mmWave) TDCM,which is composed of reprogrammable meta-atoms embedded with positive-intrinsic-negative diodes.By controlling the duty ratios and time delays of the digital coding sequences loaded on a TDCM,experimental results show that both amplitudes and phases of different harmonics can be engineered at will simultaneously and precisely in broad frequency band from 22 to33 GHz,even when the coding states are imperfect,which is in good agreement with theoretical calculations.Based on the fabricated high-performance TDCM,we further propose and experimentally realize a large-capacity mmWave wireless communication system,where 256 quadrature amplitude modulation,along with other schemes,is demonstrated.The new wireless communication system has a much simpler architecture than the currently used mmWave wireless systems,and hence can significantly reduce the hardware cost.We believe that the proposed method and system architecture can find vast application in future mmWave and terahertz-wave wireless communication and radar systems. | Ming Zheng Chen Wankai Tang Jun Yan Dai Jun Chen Ke Lei Zhang Cheng Zhang Jin Yang Lianlin Li Qiang Cheng Shi Jin Tie Jun Cui | 2022 | National Science Review2022,9,1: | 13 |
| 9 | Interference-assisted kaleidoscopic meta-plexer for arbitrary spin-wavefront manipulation显示文摘Achieving simultaneous polarization and wavefront control,especially circular polarization with the auxiliary degree of freedom of light and spin angular momentum,is of fundamental importance in many optical applications.Interferences are typically undesirable in highly integrated photonic circuits and metasurfaces.Here,we propose an interference-assisted metasurface-multiplexer(meta-plexer)that counterintuitively exploits constructive and destructive interferences between hybrid meta-atoms and realizes independent spin-selective wavefront manipulation.Such kaleidoscopic meta-plexers are experimentally demonstrated via two types of single-layer spinwavefront multiplexers that are composed of spatially rotated anisotropic meta-atoms.One type generates a spinselective Bessel-beam wavefront for spin-down light and a low scattering cross-section for stealth for spin-up light.The other type demonstrates versatile control of the vortex wavefront,which is also characterized by the orbital angular momentum of light,with frequency-switchable numbers of beams under linearly polarized wave excitation.Our findings offer a distinct interference-assisted concept for realizing advanced multifunctional photonics with arbitrary and independent spin-wavefront features.A variety of applications can be readily anticipated in optical diodes,isolators,and spin-Hall meta-devices without cascading bulky optical elements. | He-Xiu Xu Guangwei Hu Ying Li Lei Han Jianlin Zhao Yunming Sun Fang Yuan Guang-Ming Wang Zhi Hao Jiang Xiaohui Ling Tie Jun Cui Cheng-Wei Qiu | 2019 | Light(Science & Applications)2019,8,1: | 11 |
| 10 | Negative reflection and negative surface wave conversion from obliquely incident electromagnetic waves显示文摘Complete control of spatially propagating waves(PWs)and surface waves(SWs)is an ultimate goal that scientists and engineers seek for,in which negative reflection of PW and negative surface wave are two exotic phenomena.Here,we experimentally demonstrate an anisotropic digital coding metasurface capable of controlling both PWs and SWs with a single coding pattern.On the basis of the digital description of coding metasurfaces,a simple coding method is proposed to allow dual functionalities(either PW or SW manipulations)under two orthogonal polarizations at arbitrarily oblique incidences,thus improving the adaptability of digital coding metasurfaces in more practical circumstances.With elaborately designed ellipse-shaped coding particles,we experimentally demonstrate various functions under oblique incidences,including the negative reflection of PW,negative SW,anomalous reflection and their arbitrary combinations,all having good agreements with theoretical and numerical predictions.We believe that the proposed method may enable the digital coding metasurfaces to have broad applications in radar detections,wireless communications and imaging. | Shuo Liu Tie Jun Cui Ahsan Noor Zui Tao Hao Chi Zhang Guo Dong Bai Yan Yang Xiao Yang Zhou | 2018 | Light(Science & Applications)2018,7,1: | 10 |
| 11 | A plasmonic route for the integrated wireless communication of subdiffraction-limited signals显示文摘Perfect lenses,superlenses and time-reversal mirrors can support and spatially separate evanescent waves,which is the basis for detecting subwavelength information in the far field.However,the inherent limitations of these methods have prevented the development of systems to dynamically distinguish subdiffraction-limited signals.Utilizing the physical merits of spoof surface plasmon polaritons(SPPs),we demonstrate that subdiffraction-limited signals can be transmitted on planar integrated SPP channels with low loss,low channel interference,and high gain and can be radiated with a very low environmental sensitivity.Furthermore,we show how deep subdiffraction-limited signals that are spatially coupled can be distinguished after line-of-sight wireless transmission.For a visualized demonstration,we realize the high-quality wireless communication of two movies on subwavelength channels over the line of sight in real time using our plasmonic scheme,showing significant advantages over the conventional methods. | Hao Chi Zhang Le Peng Zhang Pei Hang He Jie Xu Cheng Qian Francisco J.Garcia-Vidal Tie Jun Cui | 2020 | Light(Science & Applications)2020,9,1: | 8 |
| 12 | Intelligent coding metasurface holograms by physics-assisted unsupervised generative adversarial network显示文摘Intelligent coding metasurface is a kind of information-carrying metasurface that can manipulate electromagnetic waves and associate digital information simultaneously in a smart way.One of its widely explored applications is to develop advanced schemes of dynamic holographic imaging.By now,the controlling coding sequences of the metasurface are usually designed by performing iterative approaches,including the Gerchberg–Saxton(GS)algorithm and stochastic optimization algorithm,which set a large barrier on the deployment of the intelligent coding metasurface in many practical scenarios with strong demands on high efficiency and capability.Here,we propose an efficient non-iterative algorithm for designing intelligent coding metasurface holograms in the context of unsupervised conditional generative adversarial networks(cGANs),which is referred to as physics-driven variational auto-encoder(VAE)cGAN(VAE-cGAN).Sharply different from the conventional cGAN with a harsh requirement on a large amount of manual-marked training data,the proposed VAE-cGAN behaves in a physics-driving way and thus can fundamentally remove the difficulties in the conventional cGAN.Specifically,the physical operation mechanism between the electric-field distribution and metasurface is introduced to model the VAE decoding module of the developed VAE-cGAN.Selected simulation and experimental results have been provided to demonstrate the state-of-the-art reliability and high efficiency of our VAE-cGAN.It could be faithfully expected that smart holograms could be developed by deploying our VAE-cGAN on neural network chips,finding more valuable applications in communication,microscopy,and so on. | Che Liu Wen Ming Yu Qian Ma Lianlin Li Tie Jun Cui | 2021 | Photonics Research2021,9,4: | 7 |
| 13 | Intelligent metasurfaces:control,communication and computing显示文摘Controlling electromagnetic waves and information simultaneously by information metasurfaces is of central importance in modern society.Intelligent metasurfaces are smart platforms to manipulate the wave-information-matter interactions without manual intervention by synergizing engineered ultrathin structures with active devices and algorithms,which evolve from the passive composite materials for tailoring wave-matter interactions that cannot be achieved in nature.Here,we review the recent progress of intelligent metasurfaces in wave-information-matter controls by providing the historical background and underlying physical mechanisms.Then we explore the application of intelligent metasurfaces in developing novel wireless communication architectures,with particular emphasis on metasurface-modulated backscatter wireless communications.We also explore the wave-based computing by using the intelligent metasurfaces,focusing on the emerging research direction in intelligent sensing.Finally,we comment on the challenges and highlight the potential routes for the further developments of the intelligent metasurfaces for controls,communications and computing. | Lianlin Li Hanting Zhao Che Liu Long Li Tie Jun Cui | 2022 | eLight2022,2,1: | 7 |
| 14 | Microwave metamaterials显示文摘Metamaterials are artificial structures with tailored meta-atoms at subwavelength scales to control electromagnetic waves at will.Usually,metamaterials are described by effective medium parameters(e.g.index of refraction,permittivity and permeability)due to the subwavelength nature of meta-atoms.When the meta-atom is comparable to the wavelength,the effective medium | Tie Jun Cui | 2018 | National Science Review2018,5,2: | 6 |
| 15 | Topologically Protected Edge State in Two-Dimensional Su–Schrieffer–Heeger Circuit显示文摘Topological circuits,an exciting feld just emerged over the last two years,have become a very accessible platform for realizing and exploring topological physics,with many of their physical phenomena and potential applications as yet to be discovered.In this work,we design and experimentally demonstrate a topologically nontrivial band structure and the associated topologically protected edge states in an RF circuit,which is composed of a collection of grounded capacitors connected by alternating inductors in the x and y directions,in analogy to the Su–Schriefer–Heeger model.We take full control of the topological invariant(i.e.,Zak phase)as well as the gap width of the band structure by simply tuning the circuit parameters.Excellent agreement is found between the experimental and simulation results,both showing obvious nontrivial edge state that is tightly bound to the circuit boundaries with extreme robustness against various types of defects.Te demonstration of topological properties in circuits provides a convenient and fexible platform for studying topological materials and the possibility for developing fexible circuits with highly robust circuit performance. | Shuo Liu Wenlong Gao Qian Zhang Shaojie Ma Lei Zhang Changxu Liu Yuan Jiang Xiang Tie Jun Cui Shuang Zhang | 2019 | Research2019,,1: | 6 |
| 16 | Information theory of metasurfaces显示文摘We propose a theory to characterize the information and information processing abilities of metasurfaces,and demonstrate the relation between the information of the metasurface and its radiation pattern in the far-field region.By incorporating a general aperturemodel with uncertainty relation in L2-space,we propose a theory to predict the upper bound of information contained in the radiation pattern of a metasurface,and reveal the theoretical upper limit of orthogonal radiation states.Theproposed theory also provides guidance for inverse design of the metasurface with respect to given functionalities.Through investigation of the information of disordered-phase modulated metasurfaces,we find the information invariance(1?γ,whereγis Euler’s constant)of chaotic radiation patterns.That is to say,the information of the disordered-phase modulated radiation patterns is always equal to 1?γ,regardless of variations in size,the number of elements and the phase pattern of metasurface.This value might be the lower bound of radiation-pattern information of the metasurface,which can provide a theoretical limit for information modulation applications,including computational imaging,stealth technologies and wireless communications. | Haotian Wu Guo Dong Bai Shuo Liu Lianlin Li Xiang Wan Qiang Cheng Tie Jun Cui | 2020 | National Science Review2020,7,3: | 5 |
| 17 | Intelligent metasurface imager and recognizer显示文摘There is an increasing need to remotely monitor people in daily life using radio-frequency probe signals.However,conventional systems can hardly be deployed in real-world settings since they typically require objects to either deliberately cooperate or carry a wireless active device or identification tag.To accomplish complicated successive tasks using a single device in real time,we propose the simultaneous use of a smart metasurface imager and recognizer,empowered by a network of artificial neural networks(ANNs)for adaptively controlling data flow.Here,three ANNs are employed in an integrated hierarchy,transforming measured microwave data into images of the whole human body,classifying specifically designated spots(hand and chest)within the whole image,and recognizing human hand signs instantly at a Wi-Fi frequency of 2.4 GHz.Instantaneous in situ full-scene imaging and adaptive recognition of hand signs and vital signs of multiple non-cooperative people were experimentally demonstrated.We also show that the proposed intelligent metasurface system works well even when it is passively excited by stray Wi-Fi signals that ubiquitously exist in our daily lives.The reported strategy could open up a new avenue for future smart cities,smart homes,human-device interaction interfaces,health monitoring,and safety screening free of visual privacy issues. | Lianlin Li Ya Shuang Qian Ma Haoyang Li Hanting Zhao Menglin Wei Che Liu Chenglong Hao Cheng-Wei Qiu Tie Jun Cui | 2019 | Light(Science & Applications)2019,8,1: | 5 |
| 18 | Active digital spoof plasmonics显示文摘Digital coding and digital modulation are the foundation of modern information science.The combination of digital technology with metamaterials provides a powerful scheme for spatial and temporal controls of electromagnetic waves.Such a technique,however,has thus far been limited to the control of free-space light.Its application to plasmonics to shape subwavelength fields still remains elusive.Here,we report the design and experimental realization of a tunable conformal plasmonic metasurface;which is capable of digitally coding and modulating designer surface plasmons at the deep-subwavelength scale.Based on dynamical switching between two discrete dispersion states in a controlled manner;we achieve digital modulations ofboth amplitude and phase of surface waves with nearly 100%modulation depth on a single device.Our study not only introduces a new approach for active dispersion engineering,but also constitutes an important step towards the realization of subwavelength integrated plasmonic circuits. | Hao Chi Zhang Tie Jun Cui Yu Luo Jingjing Zhang Jie Xu Pei Hang He Le Peng Zhang | 2020 | National Science Review2020,7,2: | 5 |
| 19 | Frequency-modulated continuous waves controlled by space-time-coding metasurface with nonlinearly periodic phases显示文摘The rapid development of space-time-coding metasurfaces(STCMs)offers a new avenue to manipulate spatial electromagnetic beams,waveforms,and frequency spectra simultaneously with high efficiency.To date,most studies are primarily focused on harmonic generations and independent controls of finite-order harmonics and their spatial waves,but the manipulations of continuously temporal waveforms that include much rich frequency spectral components are still limited in both theory and experiment based on STCM.Here,we propose a theoretical framework and method to generate frequency-modulated continuous waves(FMCWs)and control their spatial propagation behaviors simultaneously via a novel STCM with nonlinearly periodic phases.Since the carrier frequency of FMCW changes with time rapidly,we can produce customized time-varying reflection phases at will by the required FMCW under the illumination of a monochromatic wave.More importantly,the propagation directions of the time-varying beams can be controlled by encoding the metasurface with different initial phase gradients.A programmable STCM prototype with a full-phase range is designed and fabricated to realize reprogrammable FMCW functions,and experimental results show good agreement with the theoretical analyses. | Jun Chen Ke Jun Yan Dai Jun Wei Zhang Zhanye Chen Ming Zheng Chen Yunfeng Lu Lei Zhang Li Wang Qun Yan Zhou Long Li Jin Shan Ding Qiang Cheng Tie Jun Cui | 2022 | Light(Science & Applications)2022,11,10: | 4 |
| 20 | Space-Time-Coding Digital Metasurfaces:Principles and Applications显示文摘Space-time-modulated metastructures characterized by spatiotemporally varying properties have recently attracted great interest and become one of the most fascinating and promising research fields.In the meantime,space-time-coding digital metasurfaces with inherently programmable natures emerge as powerful and versatile platforms for implementing the spatiotemporal modulations,which have been successfully realized and used to manipulate the electromagnetic waves in both the spectral and spatial domains.In this article,we systematically introduce the general concepts and working principles of space-time-coding digital metasurfaces and provide a comprehensive survey of recent advances and representative applications in this field.Specifically,we illustrate the examples of complicated wave manipulations,including harmonic beam control and programmable nonreciprocal effect.The fascinating strategy of space-time-coding opens the door to exciting scenarios for information systems,with abundant applications ranging from wireless communications to imaging and radars.We summarize this review by presenting the perspectives on the existing challenges and future directions in this fast-growing research field. | Lei Zhang Tie Jun Cui | 2021 | Research2021,,1: | 4 |