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Fiber-optic sensing technologies based on transmission offer an alternative to scattering-based Distributed Acoustic Sensing (DAS). Being able to interrogate fibers that are thousands of kilometers long, opens opportunities for…

The estimation of atmospheric turbulence parameters is of relevance for: a) site evaluation & characterisation; b) prediction of the point spread function; c) live assessment of error budgets and optimisation of adaptive optics performance;…

Instrumentation and Methods for Astrophysics · Physics 2018-12-19 Paulo P. Andrade , Paulo J. V. Garcia , Carlos M. Correia , Johann Kolb , Maria Inês Carvalho

Atmospheric turbulence, a common phenomenon in daily life, is primarily caused by the uneven heating of the Earth's surface. This phenomenon results in distorted and blurred acquired images or videos and can significantly impact downstream…

Computer Vision and Pattern Recognition · Computer Science 2024-02-13 Xijun Wang , Santiago López-Tapia , Aggelos K. Katsaggelos

This paper provides a framework for the incorporation of the wavefront sensor measurements in the context of observing modes in which the science camera takes millisecond exposures. In this formulation, the wavefront sensor measurements…

Instrumentation and Methods for Astrophysics · Physics 2015-06-12 Richard A. Frazin

Wave front sensing of the surface of equal phase for a propagating electromagnetic wave is a vital technology in fields ranging from real time adaptive optics, to high accuracy metrology, to medical optometry. We have developed a new method…

Optics · Physics 2025-10-01 C. L. Carilli , L. Torino , B. Nikolic , N. Thyagarajan , U. Iriso

Modern adaptive optics (AO) systems for large telescopes require tomographic techniques to reconstruct the phase aberrations induced by the turbulent atmosphere along a line of sight to a target which is angularly separated from the guide…

Instrumentation and Methods for Astrophysics · Physics 2015-06-03 James Osborn , Francisco Javier De Cos Juez , Dani Guzman , Timothy Butterley , Richard Myers , Andres Guesalaga , Jesus Laine

Compressive sensing is used to perform high-dimensional quantum channel estimation with classical light. As an example, we perform a numerical simulation for the case of a three-dimensional classically non-separable state that is propagated…

Quantum Physics · Physics 2020-01-15 Chemist M. Mabena , Filippus S. Roux

Deformable mirrors with very high order correction generally have smaller dynamic range of motion than what is required to correct seeing over large aperture telescopes. As a result, systems will need to have an architecture that employs…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Donald Gavel , Andrew Norton

The performance of an adaptive optics (AO) system on a 100m diameter ground based telescope working in the visible range of the spectrum is computed using an analytical approach. The target Strehl ratio of 60% is achieved at 0.5um with a…

Astrophysics · Physics 2009-10-31 M. Le Louarn , N. Hubin , M. Sarazin , A. Tokovinin

A defocused image of a bright single star in a small telescope contains rich information on the optical turbulence, i.e. the seeing. The concept of a novel turbulence monitor based on recording sequences of ring-like intrafocal images and…

Instrumentation and Methods for Astrophysics · Physics 2021-01-13 Andrei Tokovinin

Shack-Hartmann wavefront sensors for both solar and laser guide star adaptive optics (with elongated spots) need to observe extended objects. Correlation techniques have been successfully employed to measure the wavefront gradient in solar…

Instrumentation and Methods for Astrophysics · Physics 2018-09-11 M. J. Townson , G. D Love , C. D. Saunter

We use spatio-temporal cross-correlations of slopes from five Shack-Hartmann wavefront sensors to analyse the temporal evolution of the atmospheric turbulence layers at different altitudes. The focus is on the verification of the frozen…

Instrumentation and Methods for Astrophysics · Physics 2014-02-28 Andrés Guesalaga , Benoit Neichel , Angela Cortes , Clémentine Béchet , Dani Guzmán

Predictive wavefront control is an important and rapidly developing field of adaptive optics (AO). Through the prediction of future wavefront effects, the inherent AO system servo-lag caused by the measurement, computation, and application…

Instrumentation and Methods for Astrophysics · Physics 2021-03-12 Robin Swanson , Masen Lamb , Carlos Correia , Suresh Sivanandam , Kiriakos Kutulakos

We investigate the focal plane wavefront sensing technique, known as Phase Diversity, at the scientific focal plane of a segmented mirror telescope with an adaptive optics (AO) system. We specifically consider an optical system imaging a…

Instrumentation and Methods for Astrophysics · Physics 2021-05-03 Masen Lamb , Carlos Correia , Suresh Sivanandam , Robin Swanson , Polina Zavyalova

Some optical measurements require relative timing of intensity variations with accuracy much finer than the camera frame period. One motivating example is dynamic aurora, where different prompt emissions are expected to originate from…

Space Physics · Physics 2026-05-29 Juha Vierinen , Pavithiran Sivasothy , Björn Gustavsson

We present a new kind of varifocal mirror with independently adjustable curvatures in the major directions. For actuation we use two stacked piezo bending actuators with crossed in-plane polarization. This mirror can be used for example as…

Optics · Physics 2013-11-15 Moritz Stürmer , Matthias C. Wapler , Jens Brunne , Ulrike Wallrabe

Three-dimensional shape sensing in soft and continuum robotics is a crucial aspect for stable actuation and control in fields such as Minimally Invasive surgery, as the estimation of complex curvatures while using continuum robotic tools is…

Signal Processing · Electrical Eng. & Systems 2024-03-26 Dalia Osman , Xinli Du , Timothy Minton , Yohan Noh

The Adaptive Optics Lucky Imager (AOLI) is a new instrument under development to demonstrate near diffraction limited imaging in the visible on large ground-based telescopes. We present the adaptive optics system being designed for the…

The Adaptive Optics Facility (AOF) project envisages transforming one of the VLT units into an adaptive telescope and providing its ESO (European Southern Observatory) second generation instruments with turbulence corrected wavefronts. For…

Instrumentation and Methods for Astrophysics · Physics 2015-06-23 A. Garcia-Rissmann , A. Guesalaga , J. Kolb , M. Le Louarn , P. -Y. Madec , B. Neichel

Direct measurement of the moment-curvature response of sheets or wires up to high curvatures can aid in modeling creasing, pleating, and other forming operations. We consider theoretical issues related to the geometry of pure bending. We…

Soft Condensed Matter · Physics 2020-02-03 Tian Yu , J. A. Hanna