Journal ArticleDOI
The multidither principle in adaptive optics
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TLDR
A servo signal-to-noise analysis indicates how the optimum choice of dither magnitude depends on the system noise, and many modes of operating these systems are briefly reviewed.Abstract:
Coherent optical adaptive techniques (COAT) offer promise for overcoming the deleterious effects of phase distortions experienced by optical beams propagating through distorting optics or via a turbulent and absorbing atmosphere. The theory of four classes of such systems, which employ similar multidither principles, is explored. Many modes of operating these systems are briefly reviewed and a detailed analysis of the most widely employed—a glint referencing system with sinusoidal dithers—is developed. A servo signal-to-noise analysis indicates how the optimum choice of dither magnitude depends on the system noise.read more
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Stochastic parallel-gradient-descent technique for high-resolution wave-front phase-distortion correction
TL;DR: In this article, a stochastic parallel-gradient descent (SGP) based adaptive wave-front correction algorithm is proposed for high-resolution adaptive wavefront correction, and a performance criterion for parallel-perturbation-based algorithms is introduced and applied to optimize adaptive system architecture.
Journal ArticleDOI
Adaptive optics based on analog parallel stochastic optimization: analysis and experimental demonstration
TL;DR: In this paper, a very large-scale integration (VLSI) system implementing a simultaneous perturbation stochastic approximation optimization algorithm was applied for real-time adaptive control of multielement wave-front correctors.
Journal ArticleDOI
Coherent beam combination of 1.08 kW fiber amplifier array using single frequency dithering technique.
Yanxing Ma,Xiaolin Wang,Jinyong Leng,Hu Xiao,Xiaolin Dong,Jiajian Zhu,Wenbo Du,Pu Zhou,Xiaojun Xu,Lei Si,Zejin Liu,Yijun Zhao +11 more
TL;DR: Coherent beam combination of a 1.08 kW fiber amplifier array has been demonstrated for the first time and the fringe contrast of the far-field intensity pattern is improved to more than 85%, and the residual phase error is less than λ/15.
Journal ArticleDOI
Astronomical speckle imaging
TL;DR: The many methods suggested and (some of them) tried out experimentally and/or observationally for imaging celestial objects through the Earth's atmosphere are reviewed in this paper, where their theoretical and physical bases are examined.
Journal ArticleDOI
Creating correct blur and its effect on accommodation.
TL;DR: It is found that accommodation is not driven at all by conventional rendering methods, but that it is driven surprisingly quickly and accurately by the method with defocus and chromatic aberration incorporated.
References
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Journal Article
Adaptive arrays
TL;DR: A method for adaptively optimizing the signal-to-noise ratio of an array antenna is presented and the relation of the adaptive array to sidelobe cancellation is shown, and a real-time adaptive implementation is discussed.
Journal ArticleDOI
Real-time correction of atmospherically degraded telescope images through image sharpening
TL;DR: In this paper, a new technique for the correction of atmospheric distortion in telescope images is presented, where active optical elements, set to maximize the sharpness, correct most of the atmospheric distortion caused by a random phase variation of the incoming light across the telescope aperture.
Journal ArticleDOI
Coherent Optical Adaptive Techniques
William B. Bridges,P. T. Brunner,S. P. Lazzara,T. A. Nussmeier,T. R. O’Meara,J. A. Sanguinet,W. P. Brown +6 more
TL;DR: The theory of multidither adaptive optical radar phased arrays is briefly reviewed as an introduction to the experimental results obtained with seven-element linear and three-element triangular array systems operating at 0.6328 microm.
Journal ArticleDOI
White Light Extended Source Shearing Interferometer
TL;DR: A grating lateral shear interferometer is described that can be used with a white light source and the use of the interferometers with certain types of extended sources is demonstrated.
Journal ArticleDOI
Coherent optical adaptive techniques: design and performance of an 18-element visible multidither COAT system
TL;DR: An 18-element, visible wavelength, multidither COAT system is described, based on the results of an extensive computer simulation, that uses an array of beam splitters, phase shifters, and beam combiners to form the output array.