Results 171 to 180 of about 49,183 (221)
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Stellar Imager: wavefront control
SPIE Proceedings, 2008Stellar Imager (SI) is a proposed 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 sensing and control is required to maintain alignment during science observations and after array ...
Richard G. Lyon +5 more
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Wavefront and Polarization Control with Metasurfaces
Imaging and Applied Optics 2015, 2015Optically/electrically-thin metasurfaces that can steer, focus, and manipulate the polarization of transmitted electromagnetic waves are developed using systematic design procedures and planar fabrication processes.
Carl Pfeiffer, Anthony Grbic
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Programmable Wavefront Control with Photopolymers
Controlling Light with Light: Photorefractive Effects, Photosensitivity, Fiber Gratings, Photonic Materials and More, 2007By 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 +4 more
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Modal wavefront control system
Conference on Laser and Electrooptical Systems, 1976A 9-channel 100-Hz closed-loop modal multidither COAT (Coherent Optical Adaptive Technique) system is described that could be used to improve propagation of a laser beam through the atmosphere and compensate for system induced optical aberrations.
C. Neufeld, E. L. Sloan, M. L. Skolnick
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Optimal wavefront control for adaptive segmented mirrors
Applied Optics, 1989A 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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Algorithm design for image-based wavefront control without wavefront sensing
Optical Instrument Science, Technology, and Applications, 2018Active 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 +2 more
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Wavelet-based wavefront control
SPIE Proceedings, 2004The 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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Optimal modal Fourier-transform wavefront control
Journal of the Optical Society of America A, 2005Optimal 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
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Modeling of Wavefront Control Systems
2011In 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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Plasmonic metamaterials for optical wavefront control
Frontiers in Optics 2011/Laser Science XXVII, 2011We 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
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