M. Beaulieu, L. Abe, P. Martinez, P. Baudoz C. Gouvret High-contrast imaging at small separation impact of optical configuration on wavefront shaping performances M. Beaulieu, L. Abe, P. Martinez, P. Baudoz C. Gouvret

Methodology : Guyon et al, AAS, 2013 Context SPEED project Detection & characterization of exoplanet in M-dwarf HZ Methodology : Guyon et al, AAS, 2013  ELTs, High-contrast @ 1 λ/D (Vortex / PIAACMC), Wavefront shaping

Wavefront shaping & Fresnel propagation Talbot effect Phase only Amplitude only zT/8 zT/4 zT  Use 2 DMs Several frequencies/optics  end-to-end simulation

Goal Study Fresnel propagation effect on performances Determine limitations when changing the optical configuration Define optimum DMs locations Develop end-to-end simulation tool High-contrast imaging (general) simulation (SPEED) Define SPEED setup

Implementation  Adjust Criteria Baseline setup ~ 25 optics Perfect coronagraph : removes all light w/o aberrations 2 DMs ~1000 actuators Adjust Distances, optical architecture Random phase (PSD f-α, rms) Number of random phase realizations (128) Numerical implementation Dark hole computation : energy minimization (linear transformation, small phases, perfect coronagraph)  Code : PROPER / IDL / C++ (data center, 3024 cores shared with users) Criteria 5σ contrast ratio inside the dark hole

Phase number realization Numerical results 128 phase realizations, Phase number realization

Goal Study Fresnel propagation effect on performances Determine limitations when changing the optical configuration Define optimum DMs locations Develop end-to-end simulation tool High-contrast imaging (general) simulation (SPEED) Define SPEED DMs locations End-to-end simulation Analytical approach

End-to-end simulation : results 1/2 DM1 at pupil plane Optimum ~ 2 m 7

End-to-end simulation : results 2/2 Beaulieu et al, MNRAS, 2017

End-to-end simulation : results 2/2 Beaulieu et al, MNRAS, 2017

SPEED setup Beaulieu et al, MNRAS, 2017

Analytical approach 1/2 Impact of 1 out-of-pupil plane DM Approximation : simple setup z pupil DM Ef Modulation depends on DM location z Focal plane coordinates x and y (dark hole coordinates)

Analytical approach 2/2 Efficiency

Discussion 1/2 Analytical optimum distance: 0.8 à 4 λ/D

Discussion 2/2 Analytical optimum distance: 4 à 10 λ/D

Laboratory test Simple testbed to validate simulation results, acquire know-how on wavefront shaping implementation Coronagraph easy to implement Binary coronagraphic mask (checkerboard) 4 coronagraphic zones between 6 and 16 λ/D 2 DMs Simple testbed : few optics

Conclusion End-to-end simulation tool developed @ Lagrange Collaboration LESIA Study Fresnel propagation effect Define optimum DM distance Application to SPEED Require large setup @ small separation Can be analytically estimated On-going lab test to validate results Take into account pupil discontinuities (gaps, spiders…) Predict SPEED performances (implement PIAACMC, measured aberration)