Speckle Control with a remapped-pupil PIAA-coronagraph

TL;DR

This paper demonstrates a complete speckle control loop using a PIAA coronagraph, showing that remapping optics do not hinder wavefront control, enabling improved high contrast imaging at small angular separations.

Contribution

First demonstration of a complete speckle control loop with a PIAA coronagraph, proving remapping optics are transparent to wavefront control algorithms.

Findings

Speckle nulling is effective with PIAA coronagraphs.

Remapping optics do not affect wavefront control algorithms.

PIAA improves high contrast imaging at small angular separations.

Abstract

The PIAA is a now well demonstrated high contrast technique that uses an intermediate remapping of the pupil for high contrast coronagraphy (apodization), before restoring it to recover classical imaging capabilities. This paper presents the first demonstration of complete speckle control loop with one such PIAA coronagraph. We show the presence of a complete set of remapping optics (the so-called PIAA and matching inverse PIAA) is transparent to the wavefront control algorithm. Simple focal plane based wavefront control algorithms can thus be employed, without the need to model remapping effects. Using the Subaru Coronagraphic Extreme AO (SCExAO) instrument built for the Subaru Telescope, we show that a complete PIAA-coronagraph is compatible with a simple implementation of a speckle nulling technique, and demonstrate the benefit of the PIAA for high contrast imaging at small angular separation.