Dual-polarization electric field conjugation and applications for vector vortex coronagraphs

Abstract

The vector vortex coronagraph (VVC) is a leading choice for future space-based exoplanet direct imaging missions due to its simplicity and high throughput. The construction of the VVC as an azimuthally rotating half-wave plate implies a differential influence on the two orthogonal circular polarization states of incident starlight - particularly on the mapping of deformable mirror (DM) actuators to the final image plane. Traditional electric field conjugation (EFC) coupled with the VVC is capable of digging a high-contrast dark zone in one circular polarization, but the dark zone is not preserved in the orthogonal state. This paper presents an extension to the traditional EFC algorithm to find DM actuator solutions that produce a dark zone simultaneously in both circular polarizations. This dual-polarization EFC can be used in conjunction with low-leakage VVC architectures to perform high-contrast polarimetric measurements using a single coronagraph.