Updated simulation tools for Roman coronagraph PSFs

Milani, Kian; Douglas, Ewan S.; Ashcraft, Jaren N.

doi:10.1117/12.2594807

Cited by 4 publications

(6 citation statements)

References 4 publications

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“…For iEFC simulations, similar end-to-end optical models utilizing Fresnel propagation and surface errors of individual optics are used, however, the models are built utilizing POPPY 5 as the backend propagator. The agreement between the PROPER and POPPY models has been demonstrated in previous work 6 and the simulations here present the current agreement with the updated model versions as well. The primary motivation for using the POPPY models is to accelerate computations as POPPY now includes CuPy as an option for computations, enabling end-to-end propagation entirely on a GPU.…”

Section: Introductionsupporting

confidence: 84%

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

Milani,

Douglas,

Haffert

et al. 2023

Techniques and Instrumentation for Detection of Exoplanets XI

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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 ζ 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 ζ 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.

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Section: Introductionsupporting

confidence: 84%

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

Milani,

Douglas,

Haffert

et al. 2023

Techniques and Instrumentation for Detection of Exoplanets XI

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“…More comparisons of the speckles and image morphology have been done in previous works. 23 Within the physical optics model, each optic includes a surface error map that is applied to the wavefront during propagation. In all EFC and iEFC simulations, the initial state of the Fresnel model includes a DM1 flatmap correcting the pupil aberrations that improves the initial contrast for HOWFSC by more than an order of magnitude.…”

Section: Roman Spc Physical Optics Modelmentioning

confidence: 99%

“…All the code for simulations is made available through public repositories. The repository containing the end-to-end diffraction model constructed with POPPY can be found on Zenodo at https:// zenodo.org/record/8302380 31 Similarly, the repository containing the simulation material can be found at https://zenodo.org/records/8302359 32 The associated data that are required for the diffraction model along with the data obtained using iEFC can be found at https://github.com/ kian1377/cgi_phasec_poppy_data…”

Section: Code and Data Availabilitymentioning

confidence: 99%

Modeling and performance analysis of implicit electric field conjugation with two deformable mirrors applied to the Roman Coronagraph

Milani,

Douglas,

Haffert

et al. 2024

J. Astron. Telesc. Instrum. Syst.

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High-order wavefront sensing and control (HOWFSC) is key to creating a dark hole region within the coronagraphic image plane where high contrasts are achieved. The Roman Coronagraph is expected to perform its 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. The baseline HOWFSC scheme involves running EFC while observing a bright star such as ζ Puppis to create the initial dark hole followed by a slew to the science target. The new implicit EFC (iEFC) algorithm removes the optical diffraction model from the controller, making the final contrast independent of model accuracy. While previously demonstrated with a single deformable mirror, iEFC is extended to two deformable mirror systems to create annular dark holes. First, an overview of both EFC and iEFC is presented. The algorithm is then applied to the wide-field-of-view shaped pupil coronagraph (SPC-WFOV) mode designed for the Roman Space Telescope using end-to-end physical optics models. Initial noiseless monochromatic simulations demonstrate the efficacy of iEFC as well as the optimal choice of modes for the SPC-WFOV instrument. Further simulations with a 3.6% wavefront control bandpass and a broader 10% bandpass then demonstrate that iEFC can be used in broadband scenarios to achieve contrasts below 10 −8 with Roman. Finally, an electron multiplying charge-coupled device (EMCCD) model is implemented to estimate calibration times and predict the controller's performance. Here, 10 −8 contrasts are achieved with a calibration time of ∼6.8 h assuming the reference star is ζ Puppis. The results here indicate that iEFC can be a valid HOWFSC method that can mitigate the risk of model errors associated with spaceborne coronagraphs, but to maximize iEFC performance, lengthy calibration times will be required to mitigate the noise accumulated during calibration.

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“…A summary of public CGI simulation tools (both diffraction and astronomical image generation) is provided by Douglas et al 61 . Recently, the phase B CGI PROPER model was converted 62 to the POPPY 63 propagation package.…”

Section: Wavefront Propagationmentioning

confidence: 99%

“…57 We note that the detector itself does not perform photon counting, which requires postacquisition processing. A summary of public CGI simulation tools (both diffraction and astronomical image generation) is provided by Douglas et al 61 Recently, the phase B CGI PROPER model was converted 62 to the POPPY 63 propagation package.…”

Section: Publicly Available Modeling Software From the Cgi Projectmentioning

confidence: 99%

End-to-end numerical modeling of the Roman Space Telescope coronagraph

Krist,

Steeves,

Dube

et al. 2023

J. Astron. Telesc. Instrum. Syst.

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The Roman Space Telescope will have the first advanced coronagraph in space, with deformable mirrors (DMs) for wavefront control (WFC), low-order wavefront sensing and maintenance, and a photon-counting detector. It is expected to be able to detect and characterize mature, giant exoplanets in reflected visible light. Over the past decade, the performance of the coronagraph in its flight environment has been simulated with increasingly detailed diffraction and structural/thermal finite-element modeling. With the instrument now being integrated in preparation for launch within the next few years, the present state of the end-to-end modeling, including the measured flight components such as DMs, is described. The coronagraphic modes, including characteristics most readily derived from modeling, are thoroughly described. The methods for diffraction propagation, WFC, and structural and thermal finite-element modeling are detailed. The techniques and procedures developed for the instrument will serve as a foundation for future coronagraphic missions, such as the Habitable Worlds Observatory.

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Updated simulation tools for Roman coronagraph PSFs

Cited by 4 publications

References 4 publications

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

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

Modeling and performance analysis of implicit electric field conjugation with two deformable mirrors applied to the Roman Coronagraph

End-to-end numerical modeling of the Roman Space Telescope coronagraph

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