Applications of Interferometry

Abstract

In astronomy, interferometry can be traced back to 1868 when Fizeau (1867) proposed to the Académie des Sciences that this technique could be used to measure stellar diameters. This scheme consists of installing a mask with two small openings (apertures) separated in distance at the entrance of a telescope. When pointing at a star, the superposition of the two images in the focal plane, where both beams intersect, creates interference fringe (classical Young’s fringes) across the combined image, and thereby measuring the fringe visibility as a function of aperture separation. He realized that a relationship exists between the aspect of interference fringes and the angular diameter of the light source, in this case a star.