Results 91 to 100 of about 2,844,522 (254)

Automated Measurement of Highly Divergent Optical Wavefronts with a Scanning Shack-Hartmann Sensor

, 2020
In this paper, a Shack-Hartmann wavefront sensor (SHS) is combined with a mechatronic positioning system to overcome the limited dynamic range of the SHS by repositioning and reorienting the SHS.
Csencsics, Ernst; orcid:, Berlakovich, Nikolaus; orcid:, Fuerst, Martin E.; orcid:, Schitter, Georg; orcid:   +3 more
core   +1 more source

Label‐Free Super‐Resolution Imaging Using Non‐Linear Exogenous Photon Avalanche Backlight

Advanced Science, EarlyView.
Transmission avalanche backlight (TAB) microscopy turns a photon‐avalanching Tm3+:LiYF4 crystal into a nonlinear luminescent backlight. Weak attenuation by a transparent sample is amplified into strong emission modulation: image contrast increases with sample attenuation and avalanche nonlinearity (N), while the effective point spread function narrows ...
S. Karmegam, M. Szalkowski, M. Misiak, K. Prorok, D. Szymański, A. Bednarkiewicz   +5 more
wiley   +1 more source

Multi-Spectral and Single-Shot Wavefront Detection Technique Based on Neural Networks

Photonics
Conventional wavefront sensors face challenges when detecting frequency-domain information. In this study, we developed a high-precision, and fast multi-spectral wavefront detection technique based on neural networks.
Xunzheng Li, Aoyang Wang, Mao Fan, Lianghong Yu, Xiaoyan Liang   +4 more
doaj   +1 more source

Non‐Uniform Space‐Time‐Coding Modulation for Low‐Complexity Diagnostics of Reconfigurable Intelligent Surfaces

Advanced Electronic Materials, EarlyView.
A diagnostic method for reconfigurable intelligent surfaces (RIS) based on non‐uniform space‐time‐coding modulation is presented. Fault localization is achieved via amplitude‐only spectral measurements, eliminating the need for complex signal processing. A one‐to‐one mapping between harmonic components and RIS elements enables accurate detection.
Xiao Qing Chen, Lei Zhang, Yi Ning Zheng, Bing Bing Zhu, Marco Rossi, Giuseppe Castaldi, Shuo Liu, Vincenzo Galdi, Tie Jun Cui   +8 more
wiley   +1 more source

Conformal Reconfigurable Intelligent Surfaces: A Cylindrical Geometry Perspective

Advanced Electronic Materials, EarlyView.
Cylindrical reconfigurable intelligent surfaces are explored for low‐complexity beam steering using one‐bit meta‐atoms. A multi‐level modeling approach, including optimization‐based synthesis, demonstrates that even minimal hardware can support directive scattering.
Filippo Pepe, Ivan Iudice, Giuseppe Castaldi, Marco Di Renzo, Vincenzo Galdi   +4 more
wiley   +1 more source

Terahertz Channel Modeling, Estimation and Localization in RIS‐Assisted Systems

Advanced Electronic Materials, EarlyView.
Reconfigurable intelligent surfaces have become a recent intensive research focus. Based on practical applications, channel strategies for RIS‐assisted terahertz wireless communication systems are categorized into three different types: channel modeling, channel estimation, and channel localization.
Hongjing Wang, Weipeng Wang, Xuan Cong, Shiyu Wang, Gao Li, Sen Gong, Lin Huang, Hongxin Zeng, Yaxin Zhang, Ziqiang Yang   +9 more
wiley   +1 more source

A High-Speed, Wavelength Invariant, Single-Pixel Wavefront Sensor With a Digital Micromirror Device

IEEE Access, 2019
The wavefront measurement of a light beam is a complex task, which often requires a series of spatially resolved intensity measurements. For instance, a detector array may be used to measure the local phase gradient in the transverse plane of the unknown
Mitchell A. Cox, Ermes Toninelli, Ling Cheng, Miles J. Padgett, Andrew Forbes   +4 more
doaj   +1 more source

A Compact Resistively Loaded Metamaterial Absorber for 2.4 GHz RF Energy Harvesting With Impedance‐Matched Rectifier Analysis

Advanced Electronic Materials, EarlyView.
A compact resistively loaded metamaterial absorber captures RF energy at 2.4 GHz and directs most of the accepted power to modeled loads. The resonant response is confirmed experimentally for the fabricated absorber, while an impedance‐matched rectifier is evaluated through simulation. The stage‐wise results distinguish absorber, rectifier, and cascade
Md. Murad Kabir Nipun, Md. Jahedul Islam
wiley   +1 more source

Measurement and Compensation of Laser Beam Wavefront Distortion in Atmospheric Environment

Guangtongxin yanjiu
ObjectiveFree Space Optical Communication (FSOC) demonstates high confidentiality and reliability. However, atmospheric turbulence can cause beam drift, light intensity fluctuations, and phase jitter, which seriously degrades the communication ...
LI Jing, HUANG Liangbo, ZOU Yansheng, DAI Jiewen, DAI Xiaoxiao, LIU Chen   +5 more
doaj  

Physical Unclonable Functions From Microwave Metasurface Fingerprints

Advanced Electronic Materials, EarlyView.
Nominally identical metasurfaces fabricated through standard PCB processes inevitably contain microscopic fabrication imperfections. This work demonstrates that these unavoidable electromagnetic deviations can serve as unique physical unclonable fingerprints for wireless authentication.
Guanxiong Shen, Jingyi Liang, Xinyu Li, Kezhan Zhao, Jian Wei You   +4 more
wiley   +1 more source