A system level testbed for a mid-infrared beam combiner for Terrestrial Planet Finder

Direct optical detection of Earth-like planets orbiting nearby stars is the goal of the Terrestrial Planet Finder project. One instrument which may have the capability to detect such small, faint objects in proximity to the parent star is the infra-red ing interferometer. A four input beam combiner is being built to test the aspects of the beam combination and planet detection problem. This paper describes the design developed for a ground testbed. The testbed is capable of simulating the detection process for a faint planet orbiting a nearby star. The testbed includes a star and planet source with a contrast ratio of 10^-6. In the beam combiner, two infrared ing interferometers are linked to the starlight and phase chop the light from the planet, allowing its detection in the presence of the thermal radiation background.