Results 331 to 340 of about 152,963 (375)

Broadband high-efficiency cross-polarization conversion and multi-functional wavefront manipulation based on chiral structure metasurface for terahertz wave

Journal of Physics D: Applied Physics, 2019
In this paper, a broadband and high-efficient tri-layered chiral structure metasurface (CSM) for linear polarization conversion and multi-functional wavefront manipulation was proposed and investigated numerically in terahertz region.
Junpeng Fan, Yongzhi Cheng
semanticscholar   +1 more source

Off-axis digital holographic multiplexing for rapid wavefront acquisition and processing

Advances in Optics and Photonics, 2020
Off-axis holographic multiplexing involves capturing several complex wavefronts, each encoded into off-axis holograms with different interference fringe orientations, simultaneously, with a single camera acquisition.
N. Shaked, V. Micó, Maciej Trusiak, A. Kuś, Simcha K. Mirsky   +4 more
semanticscholar   +1 more source

Wavefront processing of radio-frequency wavefront data

Proceedings of the IEEE, 1984
A class of special-purpose processors is described. These processors are for use in holographic imaging systems that utilize electromagnetic waves with radio frequencies. The systems, which operate in very nearly real time, consist of arrays of receiving antennas with a receiver at each antenna.
E.L. Rope, E.E. Brundege, Gus P. Tricoles   +2 more
openaire   +2 more sources

Wavefront scatter and wavefront healing

The Journal of the Acoustical Society of America, 2001
While acoustic scattering is essentially a time domain phenomenon, studies of scattering from objects in water, and from boundaries, have often concentrated on time-independent/cw descriptions. There are, however, critical aspects of the scattering problem which become evident only in the time domain.
openaire   +2 more sources

Active wavefront sensing and wavefront control with SLMs

SPIE Proceedings, 2004
Active systems are becoming more and more prevalent in the the field of optical technology. These systems require not only means of controlling wavefronts but mostly also of sensing wavefronts. This paper shows in four examples how spatial light modulators can be utilized to perform active wavefront sensing and wavefront controlling tasks. The examples
Jan Liesener, Hans J. Tiziani, L. Seifert, Wolfgang Osten   +3 more
openaire   +2 more sources

Wavefront reconstruction error of Shack-Hartmann wavefront sensors [PDF]

Publications of the Astronomical Society of the Pacific, 1994
We have evaluated the wavefront reconstruction error for Shack-Hartmann wavefront sensors based on a series of simulations for various numbers of subapertures at various levels of measurement error in determining the Hartmann spot centroids. The optimum number of subapertures is derived for a given magnitude reference star in the cases of photon-noise ...
M. Iye, N. Takato, I. Yamaguchi
openaire   +1 more source

The optics of wavefront sensing [PDF]

Ophthalmology Clinics of North America, 2004
This article reviews the fundamental principles by which wavefront aberrometers measure ocular aberrations. Three different ways of interpreting aberration measurements are described in terms of wavefront phase, slope, and curvature. Although curvature is the more familiar concept from geometrical optics, the wave optics concept of wavefront phase is ...
openaire   +2 more sources

Machine learning for improved image-based wavefront sensing.

Optics Letters, 2018
For large amounts of wavefront error, gradient-based optimization methods for image-based wavefront sensing are unlikely to converge when the starting guess for the wavefront differs greatly from the true wavefront. We use machine learning operating on a
S. Paine, J. Fienup
semanticscholar   +1 more source

Wavefront guided ablation

American Journal of Ophthalmology, 2001
A DAPTIVE OPTICS WAS FIRST SUGGESTED IN 1953 BY astronomer Horace Babcock to remove the blurring effects of turbulence in the atmosphere on telescopic images of stars.1 The U.S. Defense Department later invested heavily in the development of adaptive optics technology to improve the effectiveness of laser weapons as part of its Star Wars Program.
Scott MacRae, David R. Williams
openaire   +3 more sources

Wavefront guided and custom wavefront refractive surgery

Acta Ophthalmologica, 2010
AbstractAbstract not ...
openaire   +2 more sources