%0 Journal Article %T First fringes with an integrated-optics beam combiner at 10 μm. A new step towards instrument miniaturization for mid-infrared interferometry %+ Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ) %A Labadie, L. %A Martín, G. %A Anheier, N. C. %A Arezki, B. %A Qiao, H. A. %A Bernacki, B. %A Kern, P. %< avec comité de lecture %@ 0004-6361 %J Astronomy and Astrophysics - A&A %I EDP Sciences %V 531 %8 2011 %D 2011 %Z 1104.2899 %Z 2011A&A...531A..48L %R 10.1051/0004-6361/201116727 %K instrumentation: high angular resolution %K instrumentation: interferometers %K methods: laboratory %K techniques: interferometric %Z Sciences of the Universe [physics] %Z Sciences of the Universe [physics]/Astrophysics [astro-ph]Journal articles %X Context. Observations of milliarcsecond-resolution scales and high dynamic range hold a central place in the exploration of distant planetary systems in order to achieve, for instance, the spectroscopic characterization of exo-Earths or the detailed mapping of their protoplanetary disc birthplace. Multi-aperture infrared interferometry, either from the ground or from space, is a very powerful technique to tackle these goals. However, significant technical efforts still need to be undertaken to achieve a simplification of these instruments if we wish to recombine the light from a large number of telescopes. Integrated-optics concepts appear to be a suitable alternative to the current conventional designs, especially if their use can be extended to a higher number of astronomical bands.
Aims: This article reports, for the first time to our knowledge, the experimental demonstration of the feasibility of an integrated-optics approach to mid-infrared beam combination for single-mode stellar interferometry.
Methods: We fabricated a two-telescope beam combiner prototype integrated on a substrate of chalcogenide glass, a material transparent from ~1 μm to ~14 μm. We developed laboratory tools to characterize in the mid-infrared the modal properties and the interferometric capabilities of our device.
Results: We obtain interferometric fringes at 10 μm and measure a mean contrast V = 0.981 ± 0.001 with high repeatability over one week and high stability over a time-period of ~5 h. We show experimentally - as well as on the basis of modeling considerations - that the component has a single-mode behavior at this wavelength, which is essential to achieve high-accuracy interferometry. From previous studies, the propagation losses are estimated to be 0.5 dB/cm for this type of component. We also discuss possible issues that may impact the interferometric contrast.
Conclusions: The IO beam combiner performs well at the tested wavelength. We also anticipate the requirement of a closer matching between the numerical apertures of the component and the (de)coupling optics to optimize the total throughput. The next step foreseen is the achievement of wide-band interferograms. %G English %2 https://insu.hal.science/insu-03624667/document %2 https://insu.hal.science/insu-03624667/file/aa16727-11.pdf %L insu-03624667 %U https://insu.hal.science/insu-03624667 %~ INSU %~ UNIV-SAVOIE %~ UGA %~ CNRS %~ UNIV-GRENOBLE1 %~ INPG %~ IRSTEA %~ CNES %~ OSUG %~ IPAG %~ AGREENIUM %~ INRAE %~ USMB-COMUE