Développement de nouveaux détecteurs multi-spectraux pour l’imagerie en infrarouge moyen à haut contraste et haute résolution angulaire – NG-MIDE

At the time NASA and Gemini observatory both announced simultaneously the first direct images of extrasolar planets and planetary systems, the quest for exoplanets is clearly one of the major topics and also challenges for the astronomy of the next decade. In this framework the main problems are the exoplanet detection and the exoplanet characterisation. In December 2006 the ESO council has given the green light to a detailed study of an European Extremely Large Telescope (E-ELT) which aims at building an infrared and optical telescope with a diameter around 40m. Concerning its instrumentation, the call for proposals for 8 A-phases studies have been issued. One of those concerns the study of a mid-infrared instrument (3.5-20 µm) called METIS. Given a foreseen diameter of 42m, and a corresponding spatial resolution of 60 milliarcsec (mas) at 10 µm (against 300 mas for the JWST/MIRI instrument), the E-ELT METIS instrument is particularly well suited for mid-infrared observations at very high-spatial resolution. In the context of exo-planetary sciences, the spatial resolution is indeed a key parameter to separate the star and the faint close-by target. However, observations from the ground at such high angular resolutions face a new problem: the atmosphere and instrument stability. Indeed, observing a faint object (such as an exoplanet or a protoplanetary dust disk) close to a bright star is highly challenging. The mid-infrared range, although aiming at much lower constrasts (10^4-10^5 vs 10^8-10^10) than in the near-infrared range, need also the development of novel and original observing techniques to overcome the stability problem. One technique solution inherited from the near-infrared range consists in imaging simultaneously (or almost) the target at 2 close wavelength. Since the star and the object (exoplanet or protoplanetary disk) have intrinsically different colors, it is possible to subtract very efficiently the starlight by offline processing. Combined with phase-mask coronography, this technique is currently the method which achieves the best levels of starlight rejection. When the optical implementation of differential imaging is highly complex and constraining, we have identified a much simpler technological solution based on the use of multi-spectral Quantum Well Infrared Photodetectors (QWIPs). Their ability to observe almost simultaneously at 2 wavelength provides naturally built-in differential imaging. THALES company has a comprehensive experience in developing and manufacturing such QWIP detectors, and is a precursor in the field of multi-spectral detectors. We propose, in partnership with THALES, to develop new mid-infrared detectors and assess their ultimate performances using the mid-infrared test-bench facility we have developed at Saclay. The ultimate goal is to provide European mid-infrared astronomy with next generation, new design, performant detectors in a highly competitive and ambitious context of next decade instrumental projects aiming at detecting and characterizing exoplanets. We ask for a 536 679 ' support for the development by our partner THALES of this new generation detectors and the further characterization in an astrophysical context on the test-bench facility we have developed at SAp. In this context, the ANR is the unique source of financial support available either at national or european levels.