A&A 483, 365-369 (2008)
DOI: 10.1051/0004-6361:20077830
Stabilising a nulling interferometer using optical path difference dithering
P. Gabor1, B. Chazelas1, F. Brachet2, M. Ollivier1, M. Decaudin1, S. Jacquinod1, A. Labèque1, and A. Léger11 Institut d'Astrophysique Spatiale, 91405 Orsay Cedex, France
e-mail: pavel.gabor@ias.u-psud.fr
2 Centre National d'Études Spatiales, 3140 Toulouse Cedex 9, France
(Received 9 May 2007 / Accepted 20 February 2008)
Abstract
Context. Nulling interferometry has been suggested as the underlying principle
for the Darwin and TPF-I exoplanet research missions.
Aims. There
are constraints both on the mean value of the nulling ratio, and on
its stability. Instrument instability noise is most detrimental
to the stability of the nulling performance.
Methods. We
applied a modified version of the classical dithering technique to
the optical path difference in the scientific beam.
Results. Using only this method,
we repeatedly stabilised the dark fringe for several hours.
This method alone sufficed to remove the 1/f component of the noise in our setup for periods of 10 min,
typically. These results indicate that performance stability
may be maintained
throughout the long-duration data acquisitions typical of
exoplanet spectroscopy.
Conclusions. We suggest that further study of possible stabilisation
strategies should be an integral part of Darwin/TPF-I research
and development.
Key words: technique: interferometric -- instrumentation: spectrographs -- space vehicles: instruments -- methods: laboratory
© ESO 2008

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