High-modulation camera for use with a non-null interferometer

Abstract

High-frequency fringe patterns found in non-null interferometric testing of aspheres require the use of special detector arrays containing small, widely spaced pixels. A sparse array camera with the ability to detect high spatial frequencies has been developed. The modulation transfer function (MTF) of the camera is measured using a sinusoidal fringe pattern generated by a Mach-Zehnder interferometer. Spatial frequencies up to 400 cycles/mm are generated and used to characterize the MTF of the camera.