Abstract

A parellel-shear interferometer was built which is able to provide the visibility of celestial objects in real time in the presence of atmospheric turbulence. The interferometer consists of two beam splitters and a modulating/shearing element and is stable and efficient. At each shear value the fringes have constant visibility, but their atmospheric-induced phase is random in time and space. A water cell modulates the optical path at a frequency above that of most atmospheric fluctuations. The modulated interference pattern is transferred via fiber optics to a bank of photomultipliers off the telescope. A set of digital lock-in amplifiers and a microprocessor give the (incoherent) sum of the fringe visibilities every few milliseconds. First observations show the promise of the technique and reveal needed refinements.

© 1985 Optical Society of America

Shearing stellar interferometer. 1: Digital data analysis scheme

Erez Ribak and Elia Leibowitz
Appl. Opt. 24(18) 3088-3093 (1985)

First fringe measurements with a phase-tracking stellar interferometer

Michael Shao and David H. Staelin
Appl. Opt. 19(9) 1519-1522 (1980)

Complex spatial coherence function: its measurement by means of a phase-modulated shearing interferometer

E. Ribak and S. G. Lipson
Appl. Opt. 20(6) 1102-1106 (1981)

Talbot interferometry with increased shear

Krzysztof Patorski
Appl. Opt. 24(24) 4448-4453 (1985)

Speckle and speckle-shearing interferometers combined for the stimultaneous determination of out-of-plane displacement and slope

R. K. Mohanty, C. Joenathan, and Rajpal S. Sirohi
Appl. Opt. 24(18) 3106-3109 (1985)