Results 71 to 80 of about 8,993 (261)

Measuring optical transmission matrices by wavefront shaping

Optics Express, 2015
The manuscript has been submitted to Optics ...
Yoon, J Yoon, Jonghee, Lee, KR Lee, Kyeo Reh, Park, J Park, Jong chan, Park, YK Park, Yong-Keun   +3 more
openaire   +5 more sources

Ultrasonic Rainbow: A Meta‐Transducer for Frequency‐Selective Elastic Wave Control via Dithering‐Based Wavenumber Tuning

Advanced Intelligent Systems, EarlyView.
A piezoelectric meta‐transducer generates an ultrasonic rainbow, steering guided elastic waves to different angles according to frequency. A dithering‐based binary electrode design enables a closer realization of the target wavenumber filter, improving directional purity and suppressing unwanted lobes. Numerical and experimental validation demonstrates
Masoud Mohammadgholiha, Jochen Moll, Kilian Tschöke, Carsten Kruska, Sylvia E. Gebhardt, Luca De Marchi   +5 more
wiley   +1 more source

Overcoming the Phase Discontinuity Problem in RIS Optimization: A Robust and Scalable Phase‐Aware Deep Regression Framework via Hybrid CNN–LSTM Architecture

Advanced Intelligent Systems, EarlyView.
The phase discontinuity problem—where the cyclic nature of phase angles causes catastrophic errors near the ±π boundary—is a fundamental obstacle in learning‐based reconfigurable intelligent surface (RIS) optimization. A phase‐aware hybrid CNN–LSTM framework resolves this by decomposing phase predictions into sine–cosine components, mapping circular ...
Seda Savaşçı Şen, Ali Çalhan, Murtaza Cicioğlu, Oğuzhan Demiryürek   +3 more
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  

Large-Aperture Real-Time Compensated Collimating Wavefront Error Detection Method

Applied Sciences, 2019
This paper proposes a real-time compensated pentaprism scanning wavefront detection method to achieve real-time compensation for scanning errors occurring during prism movement along a guide rail.
Xueliang Zhu, Dasen Wang, Fengming Nie, Bingcai Liu, Hongjun Wang, Ailing Tian   +5 more
doaj   +1 more source

The ORCA‐TWIN qCMOS Experiment I. Science Case and Commissioning at Calar Alto Observatory

Astronomische Nachrichten, EarlyView.
ABSTRACT We describe a pilot study to explore a new generation of fast and low noise CMOS image sensors for time domain astronomy, using two remote telescopes with a baseline of 1635 km. The experiment involves direct imaging with novel qCMOS image sensor technology that combines fast readout with sub‐electron readout noise.
Martin M. Roth, Paško Roje, Stella Vješnica, Stefan Cikota, Alex J. Brown, Mike Kretlow, Marco Azzaro, Santiago Reinhart, Jesús Aceituno, Harry Dawson, Carsten Denker, Torsten Enßlin, Stephan Geier, Thomas Granzer, Thomas Kupfer, Gianluca Li Causi, Samaya Nissanke, José Luis Ortiz, Fernando Pedichini, Katja Poppenhäger, Axel Schwope   +20 more
wiley   +1 more source

Wavefront Prediction for Adaptive Optics Without Wavefront Sensing Based on EfficientNetV2-S

Photonics
Adaptive optics (AO) aims to counteract wavefront distortions caused by atmospheric turbulence and inherent system errors. Aberration recovery accuracy and computational speed play crucial roles in its correction capability. To address the issues of slow
Zhiguang Zhang, Zelu Huang, Jiawei Wu, Zhaojun Yan, Xin Li, Chang Liu, Huizhen Yang   +6 more
doaj   +1 more source

Exploring wave propagation behaviors in rock: A grain‐based perspective on mineral structures

Deep Underground Science and Engineering, EarlyView.
This study investigates wave propagation in rock at the grain scale using a grain‐based model, revealing that mineral elastic modulus significantly influences wave attenuation while grain size and distribution have limited effects. A novel peak particle velocity attenuation prediction model is proposed and validated for grain‐scale wave propagation ...
Zhiyi Liao, Jiachen Xu, Kai Zhang, Changtai Zhou   +3 more
wiley   +1 more source

A new low-cost, compact, auto-phoropter for refractive assessment in developing countries

Scientific Reports, 2017
Using a phoropter to measure the refractive error is one of the most commonly used methods by ophthalmologists and optometrists. Here, we demonstrate design and fabrication of a portable automatic phoropter with no need for patient’s feedback. The system
Babak Amirsolaimani, Gholam Peyman, Jim Schwiegerling, Arkady Bablumyan, N. Peyghambarian   +4 more
doaj   +1 more source

Instability mechanism and failure characteristics of underground cavern in block system under the action of seismic waves

Deep Underground Science and Engineering, EarlyView.
Seismic waves with tensile stress, high amplitude, and low frequency are most likely to trigger block instability and sliding. Blocks with a single sliding surface are more prone to movement than those with multiple constraints, and roof‐positioned blocks are especially vulnerable to slide.
Xiao Wang, Jinxiao Liu, Gaoshuo Zhang, Wenxin Li, Changdi He   +4 more
wiley   +1 more source