Results 211 to 220 of about 504,859 (272)
Cross-fringe piston sensor for segmented optics
Applied Optics, 2022 This paper presents a simple slit-mask-based sensing scheme that can be applied to a robust piston error sensor for segmented optical systems, even in space. Utilizing crossed fringes generated from multiple double-slit pairs, the sensor simultaneously detects multiple points in a segmented optical system in one shot. The experiments tested six pistons
Seichi Sato, Tadahito Mizutani
semanticscholar +4 more sources
Considerations about the differential piston for adaptive optics interferometry
SPIE Proceedings, 2000 This contribution extends a previous work where the concept of piston angular anisoplanatism was introduced and the issue of sky-coverage for large ground-based optical interferometers was raised. We obtain expressions for the temporal power spectra of phase fluctuations caused by differential piston and photon noise.
Bruno Femenía +3 more
semanticscholar +4 more sources
<title>High-accuracy white-light optical piston sensor for segmented optics</title>
SPIE Proceedings, 1993 A novel piston sensing concept is described for measuring piston over the +/- 0.5 wave range. The image of a white light point source is optically processed using a half-wave phase plate to enhance the presence of piston in the incident wavefront. The resultant point spread function is recorded on a CCD camera and analyzed using a simple intensity ...
Alan Wertheimer, Thomas W. Dey
semanticscholar +4 more sources
Adaptive optics for array telescopes using piston-and-tilt wave-front sensing
Applied Optics, 1992 A near-infrared adaptive optics system operating at approximately 50 Hz has been used to control phase errors adaptively between two mirrors of the Multiple Mirror Telescope by stabilizing the position of the interference fringe in the combined unresolved far-field image.
Peter Wizinowich +8 more
semanticscholar +4 more sources
Astronomical Telescopes + Instrumentation, 2022 The Natural Guidestar Adaptive Optics (NGAO) system of the Giant Magellan Telescope (GMT) uses a visible-light modulated pyramid wavefront sensor (PWFS) to measure the wavefront aberrations, including residual segment piston errors.
Fernando Quirós-Pacheco +6 more
openalex +2 more sources
In situ pressure calibration for piston cylinder cells via ruby fluorescence with fiber optics
Review of Scientific Instruments, 2007 A fiber-optic measurement technique is developed for estimating the pressure inside a piston cylinder cell up to approximately 4 GPa, based on the pressure-induced R1 fluorescence line shift of ruby (ruby scale).
K Koyama-Nakazawa +3 more
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MEMS mirror with tip or piston motion for use in adaptive optics
The Journal of the Acoustical Society of America, 2008 An array of high fill factor mirrors has each mirror be coupled across two deformable spring bars that are deformed using a drive. The two deformable springs are parallel to each other, and coupled together, e.g., by a cross bar. A support is coupled at one end to the cross bar and at its opposite end to the mirror. Coupled across the deformable spring
Dennis S. Greywall
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Piston alignment of segmented optical mirrors via convolutional neural networks
Optics Letters, 2018Most of the methods used today for the alignment of segmented mirrors are based on Shack-Hartman wavefront sensors. Other proposed methods are based on curvature sensors. These can be used to cross-check the measurements given by the primary method. We investigate a different approach which employs convolutional neural networks.
Dailos Guerra-Ramos +3 more
openaire +4 more sources
Wide-range, high-accuracy, white light piston sensor for segmented optics
, 1995 Optical systems with segmented mirrors require precision coalignment of their segments to attain the desired performance. A novel sensor for measuring piston over a ± 10 wave range by analyzing the image of a white light point source is described.
Alan Wertheimer
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The 17th Annual Meeting of the IEEELasers and Electro-Optics Society, 2004. LEOS 2004., 2004 David Moalem Maron +18 more
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