A new technique is presented for measuring the phase map due to aberrations in the wavefront-sensor non-common path of an adaptive optics system, for the common architecture in which wavefront-sensor and science paths are split at a dichroic. The underlying technique was originally developed to give absolute surface metrology with laboratory phaseshifting interferometers, correcting in that case for the unknown phase corruption due to imperfections in a transmission flat that contains the reference surface. As applied to an adaptive optics system, the technique makes use of simple mechanical actuation, normally available for pupil alignment, to isolate errors up- and down-stream of the dichroic. With auxiliary phase-diversity data from the science path, flexure-induced phase errors within both non-common paths may be characterized, yielding information about the temporally persistent speckles they are thought to produce.

Date Published: 1 July 2014
PDF: 8 pages
Proc. SPIE 9148, Adaptive Optics Systems IV, 91485E (1 July 2014); doi: 10.1117/12.2056413

Published in SPIE Proceedings Vol. 9148:
Adaptive Optics Systems IV
Enrico Marchetti; Laird M. Close; Jean-Pierre Véran, Editor(s)