Fast focal plane wavefront sensing as a second stage adaptive optics wavefront sensor

Abstract

Focal plane wavefront sensing and control has been identified as a crucial technology to enable high contrast imaging down to terrestrial mass, habitable zone exoplanets with future observatories. However, open questions remain as to how such algorithms should be integrated into existing systems to enable reaching their optimal performance, particularly for ground-based adaptive optics (AO). In this paper we use numerical simulations to show that a focal plane wavefront sensing and control technique running on millisecond timescales, called the Fast Atmospheric Self-coherent camera Technique (FAST), can be designed to operate as a “second stage” AO wavefront sensor (WFS), both for low and high order active wavefront control. Accordingly, we propose a closed-loop real-time controller architecture to use both an AO and FAST WFS to control a common DM.