Results 1 to 10 of about 8,993 (261)

An Approach for Spectrum Extraction Based on Canny Operator-Enabled Adaptive Edge Extraction and Centroid Localization

Photonics
In adaptive optics systems, high spatial resolution detection is a core prerequisite for achieving accurate wavefront correction. High spatial resolution wavefront measurement based on the traditional Shack-Hartmann technique is limited by the density of
Ao Li, Xinlan Ge, Zeyu Gao, Qiang Yuan, Yong Chen, Chao Yang, Licheng Zhu, Shiqing Ma, Shuai Wang, Ping Yang   +9 more
doaj   +1 more source

The range of local wavefront curvatures measurable with Shack‐Hartmann wavefront sensors [PDF]

Clinical and Experimental Optometry, 2009
Shack-Hartmann wavefront sensor systems are studied to assess the range of local wavefront curvatures that may be measured for a given choice of lenslet size and focal length and illumination beam characteristics, with special emphasis on systems design for use in wavefront eye refractors.
openaire   +2 more sources

Advancing wavefront sensing: meta Shack-Hartmann sensor enhances phase imaging

Light: Science & Applications
A meta-lens array-based Shack-Hartmann wavefront sensor has been developed to break the limits imposed by the size and curvature of traditional micro-lenses, which significantly improves both sampling density and angular resolution of phase measurement ...
Xiaoyuan Liu, Zihan Geng, Mu Ku Chen
doaj   +1 more source

Adaptive wavefront shaping for flow-field measurements

SPIE Proceedings, 2016
In this contribution we use wavefront shaping approaches for image correlation based flow-field measurements for the first time. Aberrations introduced by a single phase boundary in the detection beam path were explored. Variations of the optical path-length result in strong errors in position allocation and thus to an enhancement of the measurement ...
Koukourakis, N., Fregin, B., Büttner, L., Czarske, J. W.   +3 more
openaire   +3 more sources

Aspherical Surface Wavefront Testing Based on Multi-Directional Orthogonal Lateral Shearing Interferometry

Sensors
To overcome the limitations of phase sampling points in testing aspherical surface wavefronts using traditional interferometers, we propose a high-spatial-resolution method based on multi-directional orthogonal lateral shearing interferometry.
Yahui Zhu, Ailing Tian, Hongjun Wang, Bingcai Liu   +3 more
doaj   +1 more source

Monte Carlo simulation of interferometric measurement and wavefront shaping under influence of shot noise and camera noise

JPhys Photonics
Interferometry often serves as an essential building block of wavefront shaping systems to obtain optimal wavefront solutions. In this tutorial, we provide a Monte Carlo simulation tool to calculate the accuracy of interferometric measurements and its ...
Chunghyeong Lee, Jaeyeon Oh, Hakseok Ko, Mooseok Jang   +3 more
doaj   +1 more source

Variability of wavefront aberration measurements in small pupil sizes using a clinical Shack-Hartmann aberrometer

BMC Ophthalmology, 2004
Background Recently, instruments for the measurement of wavefront aberration in the living human eye have been widely available for clinical applications.
Pallikaris Aristophanis, Plainis Sotiris, Ginis Harilaos S   +2 more
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Measurement of XUV sources' wavefronts

Laser and Particle Beams, 2001
New fields of X-ray source applications (X-ray laser and high order harmonic generation) could appear if an intensity higher than 1012 Wcm−2 is reached. Following this goal, we have started a complete investigation of the X-ray beam wavefront both numerically and experimentally.
S. LE PAPE, PH. ZEITOUN, P. DHEZ, M. FRANÇOIS, M. IDIR, D. ROS, A. CARILLON   +6 more
openaire   +1 more source

Research on Nanometer Precision Measurement Method of High Order Even Aspheres

Applied Sciences
Optical aspheres are demanded with extremely high precision to meet functional requirements in space telescopes, extreme ultraviolet lithography, and other modern large optical systems.
Hao Xu, Junfeng Liu, Shanyong Chen
doaj   +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