High-contrast imaging stability using MEMS deformable mirror

Abstract

Direct imaging of Earth-like exoplanets in reflected starlight requires high contrast imaging systems, such as coronagraph, with starlight suppression better than 1e-10 over a broad spectral band. Such deep contrast can only be achieved by means of wavefront control techniques (e.g. speckle nulling, electric field conjugation, stroke minimization…) where deformable mirrors correct for low and mid-frequency optical aberrations. In space, the coronagraph with wavefront control will create high contrast regions using a target star before pointing to a science star. While re-pointing the space-telescope, the surface stability of the deformable mirrors will play a very important role in maintaining the high contrast regions. In the present work, we report an optical characterization and stability analysis of MEMS deformable mirrors for high contrast imaging using a vortex coronagraph in vacuum to simulate space conditions. We created high contrast regions using electric field conjugation and monitored its evolution for several hours using pair-wise estimation.