Technology Requirements and Development Path for Planet Detection by mid-IR Interferometry

摘要

Mid-infrared (10 micron band) interferometry from space is a promising technique for extrasolar planet detection and characterization. However, technology development in several areas is needed before a search for terrestrial planets can be performed with an interferometer. A key capability of such an instrument is the achievement of a deep (～ 10~(-6)), stable, broadband ( 1 octave) interferometric null, with dependence on sky angle of θ~4 or broader. This performance sets requirements on amplitude, delay, polarization, and pointing (wavefront tilt) matching between different apertures of the interferometer. The wavefront quality must be 1/1000 of a wavelength rms, probably requiring a high performance spatial filter. An additional technology challenge is to reject scattered sunlight and thermal emission from each telescope at the beam combiner optics and detector. This stray radiation will arrive at small angles to the starlight beams, making suppression difficult. The current status and suggested development path of these technologies will be discussed.