Experimental demonstration of a crossed cubes nuller for coronagraphy and interferometry

TL;DR

This paper presents the first experimental results of a new crossed-cubes nuller device, demonstrating high extinction and polarization insensitivity, with potential applications in space-based exoplanet detection.

Contribution

It introduces and experimentally validates a novel, compact, and easy-to-align achromatic phase shifter for coronagraphy and interferometry.

Findings

High extinction rate in monochromatic light

Device is insensitive to polarization

Suitable for space missions searching for exoplanets

Abstract

In this communication we present the first experimental results obtained on the Crossed-cubes nuller (CCN), that is a new type of Achromatic phase shifter (APS) based on a pair of crossed beamsplitter cubes. We review the general principle of the CCN, now restricted to two interferometric outputs for achieving better performance, and describe the experimental apparatus developed in our laboratory. It is cheap, compact, and easy to align. The results demonstrate a high extinction rate in monochromatic light and confirm that the device is insensitive to its polarization state. Finally, the first lessons from the experiment are summarized and discussed in view of future space missions searching for extra-solar planets located in the habitable zone, either based on a coronagraphic telescope or a sparse-aperture nulling interferometer