Optical vortex coronagraphs on ground-based telescopes

TL;DR

This paper evaluates the effectiveness of optical vortex coronagraphs on ground-based telescopes with central obscurations and atmospheric turbulence, comparing their performance to other designs and discussing practical implementation issues.

Contribution

It provides an analysis of optical vortex coronagraph performance under realistic ground-based telescope conditions and compares it with alternative coronagraph designs.

Findings

Optical vortex coronagraphs perform similarly to other designs with obscured telescopes.

Performance depends on small off-axis response and focal plane uniformity.

Manufacturability and tolerances are critical for practical implementation.

Abstract

The optical vortex coronagraph is potentially a remarkably effective device, at least for an ideal unobstructed telescope. Most ground-based telescopes however suffer from central obscuration and also have to operate through the aberrations of the turbulent atmosphere. This note analyzes the performance of the optical vortex in these circumstances and compares to some other designs, showing that it performs similarly in this situation. There is a large class of coronagraphs of this general type, and choosing between them in particular applications depends on details of performance at small off-axis distances and uniformity of response in the focal plane. Issues of manufacturability to the necessary tolerances are also likely to be important.