Numerical Simulation of a High-contrast Imaging Coronagraph Based on Pupil Apodization and Phase Corrections

Abstract A high-contrast imaging coronagraph plays a significant role in the direct detection of exoplanets. We propose a robust technique based on pupil apodization and phase corrections for high-contrast imaging of Earth mass to Jupiter mass planets and achieve contrast on the order of 10 −9 with a 5% wavelength bandwidth and wave front aberrations from actual coronagraph. We employ a 48-ring circular step-transmission apodized pupil for pupil apodization. By constraining the difference in neighboring band transmittance to make the transmittance curve smooth, we overcome the manufacturing process difficulties caused by the sharp transmittance jumps in traditional schemes, thereby ensuring processing accuracy. The wave front phase correction is achieved by using a 32 by 32 deformable mirror. Pupil apodization and phase correction are optimized by using the sequential quadratic programming algorithm to minimize energy within the working area in the focal plane. The average imaging contrast reaches the order of 10 −9 under ideal monochromatic conditions, which degrades to 10 −4 due to 5% bandwidth and wave front aberrations. After optimization, it can be restored to 10 −9 . This technique validates the feasibility and robustness for achieving high contrast under practical engineering conditions, supporting its potential application for future research on the detection and characterization of Earth-like exoplanets.