Simple Fourier optics formalism for high angular resolution systems and nulling interferometry

TL;DR

This paper introduces a simple Fourier optics formalism for designing and analyzing high angular resolution optical systems and nulling interferometers, assessing various innovative configurations and their performance limits.

Contribution

It presents a unified Fourier optics approach applicable to diverse high-resolution systems, including novel designs like super-resolving telescopes and free-flying interferometers.

Findings

Performance limited by individual telescope diameter

Formalism enables fast, accurate system analysis

Unusual designs show potential for enhanced imaging and nulling

Abstract

In this paper are reviewed various designs of advanced, multi-aperture optical systems dedicated to high angular resolution imaging or to the detection of exo-planets by nulling interferometry. A simple Fourier optics formalism applicable to both imaging arrays and nulling interferometers is presented, allowing to derive their basic theoretical relationships as convolution or cross correlation products suitable for fast and accurate computation. Several unusual designs, such as a super-resolving telescope utilizing a mosaicking observation procedure or a free-flying, axially recombined interferometer are examined, and their performance in terms of imaging and nulling capacity are assessed. In all considered cases, it is found that the limiting parameter is the diameter of the individual telescopes. The entire study is only valid in the frame of first-order geometrical optics and scalar diffraction theory. Furthermore, it is assumed that all entrance sub-apertures are optically conjugated with their associated exit pupils, a particularity inducing an instrumental behavior comparable with those of diffraction gratings.