Results 81 to 90 of about 3,540,237 (277)

Lessons from nature: biomimetic subwavelength structures for high-performance optics

, 2011
In nature, optical structures in the subwavelength range have been evolved over millions of years. For example, in the form of ‘moth-eye’ structures they show a strong antireflective effect on the compound eyes of night-active insects and therefore offer
C. Pacholski, R. Brunner, Brunner, R., J. Spatz, Sandfuchs, O., Morhard, C., O. Sandfuchs, C. Morhard, Pacholski, C., Spatz, J.   +9 more
core   +1 more source

Photonic Time Crystals and Time‐Varying Electromagnetic Metamatter: A New Direction for Ultrafast Tunable Photonic and Microwave Materials and Devices

Advanced Science, EarlyView.
Photonic time crystals (PTCs) are systems in which electromagnetic parameters are modulated periodically in time, producing momentum bandgaps via temporal scattering rather than spatial Bragg processes. This review examines the theoretical frameworks, modeling, and computational tools for time‐varying media, and summarizes experimental demonstrations ...
Ranjan Kumar Patel, Shriram Ramanathan, Ronald P. Jenkins, Michael J. Carter   +3 more
wiley   +1 more source

Dynamically Electrically Tunable Broadband Absorber Based on Graphene Analog of Electromagnetically Induced Transparency

IEEE Photonics Journal, 2016
A broadband absorber, which is composed of graphene analog of electromagnetically induced transparency (EIT) and a metal ground plane spaced by a thin SiO 2 dielectric layer, is proposed and investigated.
Gang Yao, Furi Ling, Jin Yue, Chunya Luo, Qin Luo, Jianquan Yao   +5 more
doaj   +1 more source

Kresling Origami‐Based Metamaterial Robot for Dynamic Electromagnetic Control

Advanced Science, EarlyView.
A reconfigurable metamaterial system integrates deformable origami units with high‐permittivity ceramic plates. Pneumatic switching between structural states alters local resonance conditions, enabling dynamic radar stealth and adaptive microwave reflection for mobile communication.
Xinxi Zeng, Long Zhou, Shaojie Xi, Yixuan Gao, Desheng Pan, Chaoyang Sun, Haoxin Sun, Xian Wang, Lingyun Qian, Peipei Li, Pengfei Zhu, Bo Li, Jiang Luo, Ji Zhou   +13 more
wiley   +1 more source

High Extinction Ratio and Broadband Silicon TE-Pass Polarizer Using Subwavelength Grating Index Engineering

IEEE Photonics Journal, 2015
We propose and experimentally demonstrate a novel approach to implement a low-loss, broadband, and compact transverse electric (TE)-pass polarizer on a silicon-on-insulator platform.
Yule Xiong, Dan-Xia Xu, Jens H. Schmid, Pavel Cheben, Winnie N. Ye   +4 more
doaj   +1 more source

Absorption of Broadband Low‐Frequency Sound Beyond the Thermodynamics Limit: An Acoustic Resonator With Magnetic Bearing

Advanced Science, EarlyView.
This work presents a magnetic‐bearing acoustic resonator that overcomes the thermodynamics limit of sound absorption. By introducing tunable negative stiffness, it achieves broadband low‐frequency absorption within a compact cavity, far exceeding the performance achievable by classic mass‐tuned designs.
Ying Hu, Zhe Zhang, Bohua Huang, Xue Han, Hallam Bastin Kilcoyne, Lixi Huang   +5 more
wiley   +1 more source

Anomalous wavefront manipulation and broadband sound absorption by metasurfaces with periodic subwavelength modulation

AIP Advances, 2018
Both periodic subwavelength structures and phase gradient metasurfaces have opened up new degrees of freedom to manipulate the acoustic waves respectively.
Li Cai, Jihong Wen, Dianlong Yu, Zhimiao Lu, Xing Chen, Xiang Zhao   +5 more
doaj   +1 more source

Silicon-on-Nitride Waveguide With Ultralow Dispersion Over an Octave-Spanning Mid-Infrared Wavelength Range

IEEE Photonics Journal, 2012
The proposed silicon-on-nitride (SON) waveguide exhibits an ultrabroadband (4200 nm), low chromatic dispersion in the mid-infrared (MIR) wavelength region from 2430 to 6630 nm. It has two zero-dispersion wavelengths within the span.
Yang Yue, Lin Zhang, Hao Huang, Raymond G. Beausoleil, Alan E. Willner   +4 more
doaj   +1 more source

Generation and Enhancement of Persistent Nanoscale Magnetization in All‐Dielectric Metasurfaces by Optically Injected and Localized Free Carriers

Advanced Science, EarlyView.
Infrared metasurface‐guided waves (IR‐MGW) scattered by a time interface (TI) induced by rapid, localized free‐carrier generation can be efficiently rectified to generate strong, persistent magnetic fields. We develop a rigorous, theoretical model to study a time‐varying, dispersive medium and uncover the redistribution of the initial energy of the IR ...
Shivaksh Rawat, Samyobrata Mukherjee, Gennady Shvets   +2 more
wiley   +1 more source

Space‐Time Metasurface Antenna Enabled High‐Dimensional Electromagnetic Modulation for Intrinsic Physical Layer Security

Advanced Science, EarlyView.
The concept of high‐dimensional EM modulation using the STMA for physical layer secure communication is illustrated in figure. The STMA consists of a series of programmable unit cells, with 1‐bit reconfigurable phase states (0/π). The STMA is excited by a monochromatic continuous wave (CW) at frequency fc and controlled by a field‐programmable gate ...
Xinyu Fang, Yiqing Sun, Chenfeng Yang, Siran Wang, Zheng Xing Wang, Kaixu Wang, Geng‐Bo Wu   +6 more
wiley   +1 more source