title: Common path interferometric wavefront sensor for extreme adaptive optics.
abstract: We describe a method of implementing a common-path phase-shifting point diffraction interferometric wavefront sensor suitable for extreme adaptive optics. The sensor simultaneously gives two phase-shifted outputs which can be used to drive a phase-only wavefront corrector. The device can also give a null output which can be used to calibrate any scintillation. Simulations are performed showing the utility of the device and experimental results of a high speed single channel closed loop system are presented.
authors.forename: Gordon
authors.initials: G
authors.lastname: Love
authors.forename: Thomas
authors.initials: T
authors.lastname: Oag
authors.forename: Andrew
authors.initials: A
authors.lastname: Kirby