Results 241 to 250 of about 48,988 (289)

Optimal modal Fourier-transform wavefront control

Journal of the Optical Society of America A, 2005
Optimal modal Fourier-transform wavefront control combines the speed of Fourier-transform reconstruction (FTR) with real-time optimization of modal gains to form a fast, adaptive wavefront control scheme. Our modal basis is the real Fourier basis, which allows direct control of specific regions of the point-spread function.
Poyneer, Lisa, Véran, Jean-Pierre
openaire   +3 more sources

Algorithm design for image-based wavefront control without wavefront sensing

Optical Instrument Science, Technology, and Applications, 2018
Active optics is an enabling technology for future large space telescopes. Image-based wavefront control uses an image-sharpness metric to evaluate the optical performance. A control algorithm iteratively adapts a corrective element to maximize this metric, without reconstructing the wavefront.
Ulrich Wittrock, Sven Verpoort, Orestis Kazasidis   +2 more
openaire   +1 more source

Programmable Wavefront Control with Photopolymers

Controlling Light with Light: Photorefractive Effects, Photosensitivity, Fiber Gratings, Photonic Materials and More, 2007
By controlling the photocuring of polymer systems between optical substrates it is possible to accurately program a wide variety of wavefront patterns. Two distinct methods are described, and examples of programmed wavefront elements are presented.
Lawrence Sverdrup, Jeff Chomyn, Gomaa Abdelsadek, Jagdish Jethmalani, Andreas Dreher   +4 more
openaire   +1 more source

Wavelet-based wavefront control

SPIE Proceedings, 2004
The objective of Adaptive Optics is to achieve dynamic correction of severely abberated systems. This effort will develop a novel adaptive optics approach based on wavelets. Distortions are imprinted on the wavefront in the form of a spatially varying phase field. A wavelet-based method is being developed to subtract out distortions to yield a fully
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Fizeau interferometry testbed: wavefront control

SPIE Proceedings, 2004
Stellar Imager (SI) is a potential NASA space-based UV imaging interferometer to resolve the stellar disks of nearby stars. SI would consist of 20 - 30 separate spacecraft flying in formation at the Earth-Sun L2 libration point. Onboard wavefront control would be required to initially align the formation and maintain alignment during science ...
Richard G. Lyon, Kenneth G. Carpenter, Lisa Mazzuca, Hubert Huet, Paul W. Cottle, Peter P. Petrone III, Peter Dagoda, Peter Liiva, Joe Marzouk, Gregory Solyar, David Mozurkewich, Xiaolei Zhang, Thomas Armstrong   +12 more
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Wavefront control testbed experimental results

SPIE Proceedings, 2004
The Wavefront Control Testbed (WCT) was created to develop and test wavefront sensing and control algorithms and software for the segmented James Webb Space Telescope (JWST). Last year, we changed the system configuration from three sparse aperture segments to a filled aperture with three pie shaped segments.
Laura A. Burns, Scott A. Basinger, Scott D. Campion, Jessica A. Faust, Lee D. Feinberg, Joseph J. Green, William L. Hayden, Andrew E. Lowman, Catherine M. Ohara, Peter P. Petrone III, David C. Redding, Fang Shi, David Van Buren, Barbara Zukowski   +13 more
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Optimal wavefront control for adaptive segmented mirrors

Applied Optics, 1989
A ground-based astronomical telescope with a segmented primary mirror will suffer image-degrading wavefront aberrations from at least two sources: (1) atmospheric turbulence and (2) segment misalignment or figure errors of the mirror itself. This paper describes the derivation of a mirror control feedback matrix that assumes the presence of both types ...
J D, Downie, J W, Goodman
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Modeling of Wavefront Control Systems

2011
In Sect. 5.5, we introduced typical components of telescope wavefront control systems and explained their operation principles. We noted that wavefront control systems include wavefront sensors to measure optical quality, controllers that determine which control action to take, and actuation systems that adjust form or position of optical elements.We ...
Torben Andersen, Anita Enmark
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Keck Adaptive Optics: Wavefront Control Subsystem

Adaptive Optics, 1996
Adaptive optics on the Keck 10 meter telescope will provide an unprecedented level of capability in highresolution ground-based astronomical imaging [1,2]. The system is designed to provide near diffraction limited imaging performance with Strehl > 0.3 n median Keck seeing of r0 = 25 cm, t0 = 10 msec at 500 nm wavelength. The system will be equipped
J. Brase, J. An, K. A. Avicola, D. Gavel, C. Max, S. Olivier, K. Waltjen, J. Watson, P. Wizinowich, S. Acton, A. Gleckler, T. Gregory, P. Stomski   +12 more
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Plasmonic metamaterials for optical wavefront control

Frontiers in Optics 2011/Laser Science XXVII, 2011
We discuss progress in the development of devices containing arrays of resonant apertures utilizing phase shifts accompanying resonance. We show that lenses producing three-dimensional focussing and planar quarter-wave plates can be created.
A. Roberts, L. Lin, X.M. Goh
openaire   +1 more source