Description
Adaptive Optics (AO) has become a standard requirement for large astronomical telescopes. It is used to correct, in real-time, the effects of atmospheric turbulence that cause "seeing" (image blurring). To meet the increasing demand for higher correction capabilities, many 8-meter class telescopes and most future ELTs (Extremely Large Telescopes) have implemented, or plan to implement, large-format adaptive mirrors directly within the telescope's optical train. This configuration typically prevents the calibration of these adaptive systems from being performed anywhere except directly on-sky, where the atmospheric turbulence itself interferes with and degrades the measurement process.
The objective of this thesis is to study optimal techniques for efficiently filtering the noise during the calibration process. This will involve comparing various techniques, initially through numerical simulations, and subsequently through laboratory verification.
References
Book on Adaptive Optics (AO) for astronomy in general:
J. Hardy "Adaptive Optics for Astronomical Telescopes" Oxford University Press, 1998
Brief introduction on Astronomical AO:
R. Davies, M. Kasper "Adaptive Optics for Astronomy" ARAA, 50, p305, 2012
https://doi.org/10.1146/annurev-astro-081811-125447
Focus on AO calibration, the subject of the thesis:
Kasper et al. "Fast calibration of high-order adaptive optics systems", JOSAA, 21, p1004, 2004
https://doi.org/10.1364/JOSAA.21.001004
Riccardi et al "Calibration strategy of the pyramid wavefront sensor module of ERIS with the VLT deformable secondary mirror", SPIE, 8447, p84475M, 2012
https://doi.org/10.1117/12.927122
Melmon et al, "Optimized calibration strategy for high order adaptive optics systems in closed-loop: the slope-oriented Hadamard actuation" Express, 23, p27134, 2015
https://doi.org/10.1364/OE.23.027134