Exploring the cosmic reionization and galaxy growth with AstroSat

Friday 22 October 2024

Title : Focal-plane wavefront sensing and applications: from Earth observation to astronomical imaging, laser focusing and exoplanet detection

Speaker : Laurent Mugnier (ONERA)

Abstract :

The theoretical angular resolution of an optical imaging instrument such as a telescope is given by the ratio of the imaging wavelength lambda over the aperture diameter D of the instrument. For real-world instrument, optical aberrations often prevent this so-called diffraction-limit resolution lambda/D from being achieved. The compensation of these aberrations, also called wave-front, usually requires their measurement by a wave-front sensor (WFS). The focal-plane family of sensors was born from the very natural idea that an image of a given object contains information not only about the object, but also about the wave-front. A focal-plane sensor thus requires little or no optics other than the imaging sensor; it is also the only way to be sensitive to all aberrations down to the focal plane. 

In this talk, I’ll present an overview of works at ONERA on focal-plane wave-front sensing for a variety of applications: from Earth observation to astronomical imaging, telescope segment phasing, laser focusing and exoplanet detection.