Symmetric nulling coronagraph based on a rotational shearing interferometer

We describe a fully symmetric nulling coronagraph for single-aperture telescopes that is based on a rotational shearing interferometer (RSI) and that is intended for the imaging of faint companions to nearby bright stars. In the proposed layout, all asymmetries inherent in previous single-aperture RSI-based nulling coronagraphs have been eliminated, and the bright and dark outputs are both accessible. As a result, deep, broadband, dual-polarization rejection of on-axis starlight should be possible with this system.