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Tomographic Volumetric Additive Manufacturing (TVAM) allows printing of mesoscopic objects within seconds or minutes. Tomographic patterns are illuminated onto a rotating glass vial which contains a photosensitive resin. Current pattern…

Optics · Physics 2024-03-26 Felix Wechsler , Carlo Gigli , Jorge Madrid-Wolff , Christophe Moser

Multiconjugate adaptive optics (MCAO) systems have the potential to deliver diffraction-limited images over much larger fields of view than traditional single conjugate adaptive optics systems. In MCAO, the high altitude deformable mirrors…

Solar and Stellar Astrophysics · Physics 2022-01-19 Marcos A. van Dam , Yolanda Martín Hernando , Miguel Núñez Cagigal , Luzma M. Montoya

We use telemetry data from the Gemini North ALTAIR adaptive optics system to investigate how well the commands for wavefront correction (both Tip/Tilt and high-order turbulence) can be forecasted in order to reduce lag error (due to…

Instrumentation and Methods for Astrophysics · Physics 2022-05-16 Rehan Hafeez , Finn Archinuk , Sébastien Fabbro , Hossen Teimoorinia , Jean-Pierre Véran

The orbital angular momentum (OAM) of photons is a promising degree of freedom for high-dimensional quantum key distribution (QKD). However, effectively mitigating the adverse effects of atmospheric turbulence is a persistent challenge in…

Signal Processing · Electrical Eng. & Systems 2020-06-24 Jiapeng Zhao , Yiyu Zhou , Boris Braverman , Cong Liu , Kai Pang , Nicholas K. Steinhoff , Glenn A. Tyler , Alan E. Willner , Robert W. Boyd

Adaptive optics laser guide star systems perform atmospheric correction of stellar wavefronts in two parts: stellar tip-tilt and high-spatial-order laser-correction. The requirement of a sufficiently bright guide star in the field-of-view…

Instrumentation and Methods for Astrophysics · Physics 2018-01-31 Ward S. Howard , Nicholas M. Law , Carl A. Ziegler , Christoph Baranec , Reed Riddle

Adaptive optics (AO) is a technology in modern ground-based optical telescopes to compensate the wavefront distortions caused by atmospheric turbulence. One method that allows to retrieve information about the atmosphere from telescope data…

Instrumentation and Methods for Astrophysics · Physics 2018-04-04 Tapio Helin , Stefan Kindermann , Jonatan Lehtonen , Ronny Ramlau

All coronagraphic instruments for exoplanet high-contrast imaging need wavefront correction systems to reject optical aberrations and create sufficiently dark holes. Since the most efficient wavefront correction algorithms (controllers and…

Instrumentation and Methods for Astrophysics · Physics 2018-10-09 He Sun , N. Jeremy Kasdin , Robert Vanderbei

Atmospheric wavefront prediction based on previous wavefront sensor measurements can greatly enhance the performance of adaptive optics systems. We propose an optimal linear approach based on the Empirical Orthogonal Functions (EOF)…

Instrumentation and Methods for Astrophysics · Physics 2017-07-04 Olivier Guyon , Jared Males

We are currently conceiving, through (MC) simulation, a multi-channel gamma detector array (TIARA for Time-of-flight Imaging ARrAy) for the online monitoring of protontherapy treatments. By measuring the Time-Of-Flight (TOF) between a beam…

Most adaptive optics (AO) systems using pyramid wavefront sensors (PyWFS) to estimate the phase of the pupil field use mechanical modulation of the beam in order to increase the dynamic range in low-order modes so the PyWFS can usefully…

Instrumentation and Methods for Astrophysics · Physics 2017-08-31 Richard Frazin

Time-of-flight magnetic resonance angiography (TOF-MRA) is one of the most widely used non-contrast MR imaging methods to visualize blood vessels, but due to the 3-D volume acquisition highly accelerated acquisition is necessary.…

Image and Video Processing · Electrical Eng. & Systems 2020-08-05 Hyungjin Chung , Eunju Cha , Leonard Sunwoo , Jong Chul Ye

The capability of the adaptive optics to correct for the segmentation error is analyzed in terms of the residual wavefront RMS and the power spectral density of the phase. The analytical model and the end-to-end simulation give…

Astrophysics · Physics 2009-11-11 Natalia Yaitskova , Christophe Verinaud

CANARY is the multi-object adaptive optics (MOAO) on-sky pathfinder developed in the perspective of Multi-Object Spectrograph on Extremely Large Telescopes~(ELTs). In 2013, CANARY was operated on-sky at the William Herschel telescope~(WHT),…

Instrumentation and Methods for Astrophysics · Physics 2017-02-01 O. A. Martin , É. Gendron. , G. Rousset , D. Gratadour , F. Vidal , T. J. Morris , A. G. Basden , R. M. Myers , C. M. Correia , D. Henry

This article is the second of a series of articles aiming at proving the feasibility of the forecast of all the most relevant classical atmospherical parameters for astronomical applications (wind speed and direction, temperature, relative…

Instrumentation and Methods for Astrophysics · Physics 2013-09-27 Franck Lascaux , Elena Masciadri , Luca Fini

Current and future high contrast imaging instruments aim to detect exoplanets at closer orbital separations, lower masses, and/or older ages than their predecessors. However, continually evolving speckles in the coronagraphic science image…

Instrumentation and Methods for Astrophysics · Physics 2022-06-22 Benjamin L. Gerard , Daren Dillon , Sylvain Cetre , Rebecca Jensen-Clem

Monitoring turbulence parameters is crucial in high-angular resolution astronomy for various purposes, such as optimising adaptive optics systems or fringe trackers. The former are present at most modern observatories and will remain…

Instrumentation and Methods for Astrophysics · Physics 2023-10-25 Nuno Morujão , Carlos Correia , Paulo Andrade , Julien Woillez , Paulo Garcia

This paper presents the status of an ongoing project aimed at developing a PSF reconstruction software for adaptive optics (AO) observations. In particular, we test for the first time the implementation of pyramid wave-front sensor data on…

The accuracy of wavefront reconstruction from discrete slope measurements depends on the sampling geometry, coherence length of the incoming wavefronts, wavefront sensor specifications and the accuracy of the reconstruction algorithm. Monte…

Instrumentation and Methods for Astrophysics · Physics 2009-11-08 M B Roopashree , Akondi Vyas , B Raghavendra Prasad

Many technologies have been developed to help improve spatial resolution of observational images for ground-based solar telescopes, such as adaptive optics (AO) systems and post-processing reconstruction. As any AO system correction is only…

Instrumentation and Methods for Astrophysics · Physics 2017-01-04 Xue-bao Li , Zhong Liu , Feng Wang , Zhen-yu Jin , Yong-yuan Xiang , Yan-fang Zheng

Adaptive optical correction is an efficient technique to obtain high-resolution images of the retinal surface. A main limitation of adaptive optical correction, however, is the small size of the corrected image. For medical purposes it is…

Optics · Physics 2015-03-27 Aglae Kellerer
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