Simulating the efficacy of the implicit-electric-field-conjugation algorithm for the Roman Coronagraph with noise

TL;DR

This paper evaluates the implicit Electric-Field-Conjugation (iEFC) algorithm's effectiveness for the Roman Coronagraph through simulations, including noise, to determine its viability as an alternative to traditional EFC in high-contrast imaging.

Contribution

It introduces and tests an implicit-EFC algorithm for the Roman Coronagraph, demonstrating its potential to operate without detailed optical models and assessing its performance with noise.

Findings

iEFC achieves comparable contrast to EFC in monochromatic simulations.

Broadband simulations show iEFC maintains effectiveness with realistic noise levels.

Optimal calibration modes are identified for effective iEFC response matrix generation.

Abstract

The Roman Coronagraph is expected to perform its high-order wavefront sensing and control (HOWFSC) with a ground-in-the-loop scheme due to the computational complexity of the Electric-Field-Conjugation (EFC) algorithm. This scheme provides the flexibility to alter the HOWFSC algorithm for given science objectives. A new alternative implicit-EFC algorithm is of particular interest as it requires no optical model to create a dark-hole, making the final contrast independent of the model accuracy. The intended HOWFSC scheme involves running EFC while observing a bright star such as $\zeta$ Puppis to create the initial dark-hole, then slew to the science target while maintaining the contrast with low-order WFSC over the given observation. Given a similar scheme, the efficacy of iEFC is simulated for two coronagraph modes, namely the Hybrid Lyot Coronagraph (HLC) and the wide-field-of-view Shaped-Pupil-Coronagraph (SPC-WFOV). End-to-end physical optics models for each mode serve as the tool for the simulations. Initial monochromatic simulations are presented and compared with monochromatic EFC results obtained with the FALCO software. Various sets of calibration modes are tested to understand the optimal modes to use when generating an iEFC response matrix. Further iEFC simulations are performed using broadband images with the assumption that $\zeta$ Puppis is the stellar object being observed. Shot noise, read noise, and dark current are included in the broadband simulations to determine if iEFC could be a suitable alternative to EFC for the Roman Coronagraph.