"Fast" and Furious focal-plane wavefront sensing at W. M. Keck Observatory

TL;DR

The paper demonstrates that the Fast and Furious focal-plane wavefront sensing algorithm can quickly improve on-sky adaptive optics point-spread functions, enhancing image quality for exoplanet imaging and other high-precision astronomical observations.

Contribution

It introduces and validates a simple, real-time wavefront correction method that operates concurrently with science observations at the Keck Observatory.

Findings

Significant PSF quality improvement in few iterations

Effective in narrow and broadband filters

Potential for real-time adaptive optics optimization

Abstract

High quality, repeatable point-spread functions are important for science cases like direct exoplanet imaging, high-precision astrometry, and high-resolution spectroscopy of exoplanets. For such demanding applications, the initial on-sky point-spread function delivered by the adaptive optics system can require further optimization to correct unsensed static aberrations and calibration biases. We investigated using the Fast and Furious focal-plane wavefront sensing algorithm as a potential solution. This algorithm uses a simple model of the optical system and focal plane information to measure and correct the point-spread function phase, without using defocused images, meaning it can run concurrently with science. On-sky testing demonstrated significantly improved PSF quality in only a few iterations, with both narrow and broadband filters. These results suggest this algorithm is a useful path forward for creating and maintaining high-quality, repeatable on-sky adaptive optics point-spread functions.