Detector apparatus for detecting coherent point-source radiation

摘要

Detector apparatus includes a diffraction grating (11) having a period such that the incidence of coherent point-source radiation upon it produces a number of spaced self-images of the grating behind it. A Moiré grating (12) is placed to coincide with one of these self-images and a detector array (13-16) is placed behind the Moiré grating to detect the resulting interference fringes.