Journal ArticleDOI
Active metasurface for reconfigurable reflectors
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TLDR
In this paper, a metasurface composed of active unit cells incorporating voltage-controlled varactor diodes, where the dispersion responses of the cells can be tailored, is proposed to overcome the limitations of passive surfaces.Abstract:
Metasurfaces relying solely on passive unit cells printed on a dielectric substrate present limited characteristics due to their intrinsic dispersions. A metasurface composed of active unit cells incorporating voltage-controlled varactor diodes, where the dispersion responses of the cells can be tailored, is proposed to overcome the limitations of passive metasurfaces. Two functionalities are numerically and experimentally demonstrated from the active metasurface used as an electronically reconfigurable reflector. First, we show that anomalous reflection properties can be produced within a broad frequency range and second, we show that the direction of the reflected beam can be scanned within an angular range.read more
Citations
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Journal ArticleDOI
Block Copolymer Directed Metamaterials and Metasurfaces for Novel Optical Devices
Alberto Alvarez-Fernandez,Cian Cummins,Matthias Saba,Ullrich Steiner,Guillaume Fleury,Virginie Ponsinet,Stefan Guldin +6 more
TL;DR: In this paper, the authors focus on the engineering of the optical properties for metamaterials active in the visible and near-infrared (IR) wavelength range, and highlight unexplored opportunities offered by block copolymer (BCP) self-assembly.
Journal ArticleDOI
Reconfigurable intelligent surfaces for smart wireless environments: channel estimation, system design and applications in 6G networks
Ying-Chang Liang,Jie Chen,Ruizhe Long,Zhen-Qing He,Xian Qi Lin,Chenlu Huang,Liu Shilin,Xuemin Sherman Shen,Marco Di Renzo +8 more
TL;DR: An overview of the RIS-aided wireless systems, including the reflection principle, channel estimation, and system design is provided, and two types of emerging RIS systems are considered: RIS- aided wireless communications (RAWC and RIS-based information transmission (RBIT), where the RIS plays the role of the reflector and the transmitter, respectively.
Journal ArticleDOI
Dynamically Controlling Spatial Energy Distribution with a Holographic Metamirror for Adaptive Focusing
Badreddine Ratni,Zhuochao Wang,Kuang Zhang,Xumin Ding,André de Lustrac,André de Lustrac,Gérard-Pascal Piau,Shah Nawaz Burokur +7 more
TL;DR: In this article, a holographic metamirror implementing proper phase-profile distributions necessary to dynamically control the focal spot is designed, and near-field measurements are performed to demonstrate energy focusing at predicted focal points.
Journal ArticleDOI
Ultrathin active polarization-selective metasurface at X-band frequencies
TL;DR: In this article, an ultrathin active polarization-selective metasurface is designed and optimized for operation in the X band, which provides over 35 dB of input-output isolation achieved through orthogonal polarizations, which ensures stable operation.
Journal ArticleDOI
Spatial wave control using a self-biased nonlinear metasurface at microwave frequencies
TL;DR: In this paper, a passive wideband nonlinear metasurface is manifested, which is composed of embedded L−shape and Γ−shape meta-atoms with PIN-diode elements.
References
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TL;DR: This Review focuses on recent developments on flat, ultrathin optical components dubbed 'metasurfaces' that produce abrupt changes over the scale of the free-space wavelength in the phase, amplitude and/or polarization of a light beam.
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Sub-Diffraction-Limited Optical Imaging with a Silver Superlens
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