Observatoire de Paris Institut national de recherche scientifique français Univerité Pierre et Marie Curie Université Paris Diderot - Paris 7

Fourier-based WaveFront Sensing at LAM : a quick overview

mardi 19 mars 2019, par Olivier Fauvarque (LAM)

Mercredi 20 mars 2019 à 14h00 , Lieu : Salle de conférence du bâtiment 17

At the condition to use adequate focal masks, optical Fourier filtering turns out to convert phase fluctuations into intensity variations with a great efficiency. If two wave front sensors in particular - the Pyramid and the Zernike – have, during the last decades, shown very promising performance making them serious candidates for the next AO systems of the Extremely Large Telescopes, a general and theoretical scheme to finely define their behavior was missing.

This seminar intends to present the latest theoretical results that have been done by the LAM AO team and its partners in this emerging instrumental field of research. In particular, the problem of Optical Gain tracking will be adressed through the powerful Kernel mathematical framework. We will then see how to choose proper phase reconstructor depending on the sensors’ optical characteristics. We will also introduce a new kind of optical device allowing to improve the linearity of Fourier-based WFSs without any loss of sensitivity. Finally, a presentation of the LOOPS test bench (designed to generate and test a large diversity of Fourier-based WFSensors) will serve as conclusion.

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