Abstract 323

Submitted by Olivier GUYON

Authors

O. Guyon

Affiliations

Subaru Telescope / University of Arizona

Abstract

High precision wavefront sensing is the key to detect low mass (rocky) planets with ELTs. Ideally, a wavefront sensor for an Extreme-AO system should be both very sensitive (to allow high speed wavefront correction) and very accurate (to allow precise calibration of residual starlight vs. planet light in the focal plane). I will describe two options which meet these requirements: - non-linear curvature wavefront sensing is several orders of magnitude more sensitive than conventional WFSs, and, unlike pyramid, can work at full sensitivity in open loop or in the visible - focal plane wavefront sensing combines high sensitivity and is free from non-common path errors. It can also measure light coherence, and therefore separate speckles from planets I will show that combining these two schemes is especially attractive, and can allow direct imaging of rocky planets with ELTs. Laboratory demonstration of both techniques will also be presented. A short description of the Subaru Coronagraphic Extreme AO (SCExAO) system, which is currently under assembly and will include these techniques, will be given.