Systematic errors in nulling interferometers

Abstract

Nulling interferometers combine on-axis suppression with high angular resolution, making them ideal instruments for the direct detection of faint planets close to their parent star. Analysis is developed to show that it is systematic errors, resulting from fluctuations in the null depth, that drive the instrument performance. A second-order combination of amplitude and phase errors is the dominant contributor. In the calculated example, the detection of an Earthlike planet around a Sunlike star at 15 pc requires that the arms of the interferometer must be phased to within approximately 1.5 nm and have their amplitudes matched to approximately 0.1%.