Integrated modeling of wavefront sensing and control for space telescopes utilizing active and adaptive optics

TL;DR

This paper presents an integrated model combining geometrical raytracing and physical optics to simulate wavefront sensing and control in space telescopes with active and adaptive optics, aiming for high-contrast exoplanet imaging.

Contribution

It develops a comprehensive model that accounts for on-orbit errors and active corrections, enhancing the accuracy of wavefront control simulations for space-based coronagraphs.

Findings

Quantifies starlight suppression relative to sensor SNR.

Demonstrates wavefront correction effectiveness with integrated modeling.

Highlights importance of combined geometrical and physical optics approaches.

Abstract

Extreme wavefront correction is required for coronagraphs on future space telescopes to reach 1e-8 or better starlight suppression for the direct imaging and characterization of exoplanets in reflected light. Thus, a suite of wavefront sensors working in tandem with active and adaptive optics are used to achieve stable, nanometer-level wavefront control over long observations. In order to verify wavefront control systems comprehensive and accurate integrated models are needed. These should account for any sources of on-orbit error that may degrade performance past the limit imposed by photon noise. An integrated model of wavefront sensing and control for a space-based coronagraph was created using geometrical raytracing and physical optics propagation methods. Our model concept consists of an active telescope front end in addition to a charge-6 vector vortex coronagraph instrument. The telescope uses phase retrieval to guide primary mirror bending modes and secondary mirror position to control the wavefront error within tens of nanometers. The telescope model is dependent on raytracing to simulate these active optics corrections for compensating the wavefront errors caused by misalignments and thermal gradients in optical components. Entering the coronagraph, a self-coherent camera is used for focal plane wavefront sensing and digging the dark hole. We utilize physical optics propagation to model the coronagraph's sensitivity to mid and high-order wavefront errors caused by optical surface errors and pointing jitter. We use our integrated models to quantify expected starlight suppression versus wavefront sensor signal-to-noise ratio.