Accelerated modeling of near and far-field diffraction for coronagraphic optical systems

Abstract

Accurately predicting the performance of coronagraphs and tolerancing optical surfaces for high-contrast imaging requires a detailed accounting of diffraction effects. Unlike simple Fraunhofer diffraction modeling, near and farfield diffraction effects, such as the Talbot effect, are captured by plane-to-plane propagation using Fresnel and angular spectrum propagation. This approach requires a sequence of computationally intensive Fourier transforms and quadratic phase functions, which limit the design and aberration sensitivity parameter space which can be explored at high-fidelity in the course of coronagraph design. This study presents the results of optimizing the multi-surface propagation module of the open source Physical Optics Propagation in PYthon (POPPY) package. This optimization was performed by implementing and benchmarking Fourier transforms and array operations on graphics processing units, as well as optimizing multithreaded numerical calculations using the NumExpr python library where appropriate, to speed the end-to-end simulation of observatory and coronagraph optical systems. Using realistic systems, this study demonstrates a greater than five-fold decrease in wall-clock runtime over POPPY's previous implementation and describes opportunities for further improvements in diffraction modeling performance.

Design of the vacuum high contrast imaging testbed for CDEEP, the Coronagraphic Debris and Exoplanet Exploring Pioneer

“…In between the grating and its self-image mixing between amplitude and phase is observed, which is a limiter to high contrast imaging instrument performance. 32 For small pupil sizes (such as those on MEMS DMs) the Talbot effect occurs at relatively short distances, on the order of the specified testbed footprint. Consequently, the distances between optics must be constrained with consideration for the Talbot effect so that minimal mixing between amplitude and phase will occur.…”

Topological pupil segmentation and point spread function analysis for large aperture imaging systems

“…Also, this research made use of POPPY, an open-source optical propagation Python package originally developed for the James Webb Space Telescope project. [34][35][36]…”

Optical modeling and testing of the Deformable Mirror Demonstration Mission (DeMi) CubeSat payload

“…This research made use of POPPY, an open-source optical propagation Python package originally developed for the James Webb Space Telescope project (Perrin, 2012). [19][20][21] This research also made use of matplotlib, 24 astropy, 25,26 iPython, 27 and scipy. 28…”

“…A diagram of the DeMi modeling strategy is shown in Figure4. The diffraction model has been developed using the Physical Optics Propagation in PYthon (POPPY) software package [19][20][21]. POPPY is an open-source and flexible software package developed to model Fraunhofer and Fresnel diffraction in optical systems.…”