AAS 205th Meeting, 9-13 January 2005
Session 33 Instrumentation: Ground-Based and Space-Based
Oral, Monday, January 10, 2005, 10:00-11:30am, Royal Palm 1-3

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[33.07] Quadrature Phase Interferometry: a phase-sensitive rotation shearing interferometer for diffraction-limited imaging

B. Kern, P.E. Dimotakis, C. Martin, D.B. Lang, R.N. Thessin (Caltech)

We have developed a new technique of rotation shearing interferometry, for diffraction-limited imaging through turbulence at visible wavelengths from single ground-based telescopes. While previous rotation shearing interferometers have been used in astronomical observations, none has successfully measured visibility phase in the presence of turbulent aberrations. Our technique, called Quadrature Phase Interferometery (QPI), simultaneously obtains four interferograms, each of which observes the same interferometric baselines with differing instrumental phase contributions. These instrumental phase contributions allow full determination of the complex visibility (modulus and phase) from a single exposure, over all baselines up to the telescope diameter. Turbulent phase aberrations can be averaged out of successive exposures to obtain diffraction-limited images. The expected limiting magnitudes of this technique are comparable to those of other passive techniques such as speckle interferometry or non-redundant masking. The QPI has been tested in the laboratory and at Palomar Observatory, with encouraging results. The design principles and results will be discussed. This work was supported by the National Science Foundation and the Air Force Office of Scientific Research.

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© 2004. The American Astronomical Society.