Pupil Plane Phase Apodization

TL;DR

This paper discusses phase apodization coronagraphs, specifically Apodizing Phase Plates (APPs) and vector-APPs, which achieve high-contrast imaging close to the star with insensitivity to tip/tilt errors, suitable for ground-based telescopes.

Contribution

It introduces the implementation of phase apodization coronagraphs as APPs and vector-APPs, highlighting their achromatic performance and broadband contrast capabilities.

Findings

Achieves broadband contrast of ~10^-5

Operates effectively at small angular separations

Insensitive to tip/tilt errors

Abstract

Phase apodization coronagraphs are implemented in a pupil plane to create a dark hole in the science camera focal plane. They are successfully created as "Apodizing Phase Plates" (APPs) using classical optical manufacturing, and as "vector-APPs" using liquid-crystal patterning with essentially achromatic performance. This type of coronagraph currently delivers excellent broadband contrast ($\sim$10$^{-5}$) at small angular separations (few $\lambda/D$) at ground-based telescopes, owing to their insensitivity to tip/tilt errors.