A wavefront sensor-driven variable-geometry pupil for ground-based aperture synthesis imaging

摘要

Idescribe a variable-geometry pupil (VGP) to increase image resolution for ground-based near-IR and optical imaging. In this scheme, a curvature-type wavefront snesor provides an estimate of the wavefront curvature to the controller of a high-resolution spatial light modulator (SLM) or micro-electromechanical (MEM) mirror, positioned at an image of the telescope pupil. This optical element, the VGP, passes or reflects the incident beam only where the wavefront phase is sufficikently smooth, viz, where the curvature is sufficiently low. Using a computer simulation, I show the VGP can sharpen and smooth the long-exposure PSF and increase the OTF SNR for tilt-only and low-order AO systems, allowing higher resolution and more stable deconvolution with dimmer AO guidestars.