Improved High Contrast Imaging with On-Axis Telescopes using a Multi-Stage Vortex Coronagraph

TL;DR

This paper introduces a multi-stage vortex coronagraph technique that significantly improves high contrast imaging with on-axis telescopes by reducing residual light leakage without sacrificing throughput.

Contribution

It proposes a novel multi-vortex method that enhances contrast in on-axis telescopes, overcoming limitations caused by central obscurations.

Findings

Reduces residual light leakage to (a/A)^n with n >= 4

Enables high contrast imaging with on-axis telescopes

Maintains high throughput in the imaging process

Abstract

The vortex coronagraph is one of the most promising coronagraphs for high contrast imaging because of its simplicity, small inner working angle, high throughput, and clear off-axis discovery space. However, as with most coronagraphs, centrally-obscured on-axis telescopes degrade contrast. Based on the remarkable ability of vortex coronagraphs to move light between the interior and exterior of pupils, we propose a method, based on multiple vortices, that, without sacrificing throughput, reduces the residual light leakage to (a/A)^n, with n >=4, and a and A being the radii of the central obscuration and primary mirror, respectively. This method thus enables high contrasts to be reached even with an on-axis telescope.