Boundary diffraction wave integrals for diffraction modeling of external occulters

TL;DR

This paper introduces a fast boundary diffraction wave integral method for modeling the electric field of external occulters, enabling quick adjustments for shape, position, and off-axis sources in exoplanet imaging.

Contribution

It presents a novel 2D-to-1D edge integral approach that simplifies and accelerates diffraction calculations for external occulters, improving modeling accuracy and flexibility.

Findings

The method reduces computation time for electric field modeling.

It accurately incorporates shape, position, and off-axis source effects.

The approach is adaptable for real-time adjustments in occulter design.

Abstract

An occulter is a large diffracting screen which may be flown in conjunction with a telescope to image extrasolar planets. The edge is shaped to minimize the diffracted light in a region beyond the occulter, and a telescope may be placed in this dark shadow to view an extrasolar system with the starlight removed. Errors in position, orientation, and shape of the occulter will diffract additional light into this region, and a challenge of modeling an occulter system is to accurately and quickly model these effects. We present a fast method for the calculation of electric fields following an occulter, based on the concept of the boundary diffraction wave: the 2D structure of the occulter is reduced to a 1D edge integral which directly incorporates the occulter shape, and which can be easily adjusted to include changes in occulter position and shape, as well as the effects of sources---such as exoplanets---which arrive off-axis to the occulter. The structure of a typical implementation of the algorithm is included.