Dual-aperture fiber nulling for high spatial and spectral resolution studies of exoplanets

We are developing a "dual-aperture fiber nuller" (DAFN) as a technology to bridge the gap in observation of exoplanets with orbital separations between 1-10s of AU. Such an instrument interferometrically achieves an on-axis (starlight) null while off-axis light (planet light) is transmitted to a high-resolution spectrograph. The performance of the DAFN is competitive among only a few existing technologies such as the vortex fiber nuller. Furthermore, it has the cost-effective advantage of improving angular resolution by expanding the interferometric baseline rather than increasing aperture size. We present a monochromatic demonstration of this technology's angular resolution (< 1 λ/D) and sensitivity to starlight suppression in the lab. The DAFN technology can potentially be deployed to preexisting interferometric frameworks such as the Large Binocular Telescope Interferometer or the Very Large Telescope Interferometer. It can also benefit prospective space-based exoplanet direct imaging missions, e.g. LIFE, as well as ground-based ELT searches for terrestrial planets in the habitable zone.