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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.

The SAM616 is a prototype deformable mirror built by CILAS for the Thirty Meter Telescope’s Narrow Field Infrared Adaptive Optics System (NFIRAOS). It was delivered to NRC-HAA in August 2018 for performance testing at room temperature and at the operating temperature of NFIRAOS, -30oC. Properties that were measured include the total stroke, hysteresis, creep and coupling of the actuators, as well as the flattening ability at various temperatures. The mirror has been found to meet (and in some case exceed) all its performance requirements including its flattening requirements.

High-contrast imaging instruments have advanced techniques to improve contrast, but they remain limited by uncorrected stellar speckles, often lacking a “second stage” correction to complement the Adaptive Optics (AO) correction. We are implementing a new second stage speckle-correction solution for the Gemini Planet Imager (GPI), replacing the instrument calibration unit (CAL) with the Fast Atmospheric Self coherent camera Technique (FAST), a new version of the self-coherent camera (SCC) concept. Our proposed upgrade (CAL2.0) will use a common-path interferometer design to enable speckle correction, through post-processing and/or by a feedback loop to the AO deformable mirror. FAST utilizes a new type of coronagraphic mask that will enable, for the first time, speckle correction down to millisecond timescales. The system's main goal is to improve the contrast by up to 100x in a halfdark hole to enable a new regime of science discoveries. Our team has been developing this new technology at the NRC's Extreme Wavefront control for Exoplanet and Adaptive optics Research Topics (NEW EARTH) laboratory over the past several years. The GPI CAL2.0 update is funded (November 2020), and the system’s first light is expected late 2023., Adaptive Optics Systems VII, December 14-18, 2020, Online Only, United States