Current progress on TPF-I mid-infrared achromatic nulling at the Jet Propulsion Laboratory

Infrared interferometric nulling is a promising technology for exoplanet detection. Nulling research for the Terrestrial Planet Finder Interferometer has explored several interferometer architectures at the Jet Propulsion Laboratory (JPL). The most recent efforts have focused on an architecture which employs a geometric field flip to achieve the necessary π phase delay in the interferometer. The periscope design currently in use allows for a completely achromatic phase flip. Deep interferometric nulling requires optical path stability, precision optical alignment, intensity balancing, and dispersion correction. This paper will discuss recent efforts to implement a precision optical alignment, stabilize the interferometer environment, implement optical path metrology, control intensity balance, and compensate for dispersion introduced by beamsplitter mismatch.