Real-Time Interferometer

The fundamental measurement required for proof of quality of an optical system is the shape of its transmitted wavefront. A knowledge of wavefront error and the transmission characteristics of an optical system allow calculation (at the measurement wavelength) of all commonly used quality factors such as optical transfer function, point spread function, Strehi ratio, etc. This paper describes a recently developed shearing interferometer that is designed for general purpose laboratory use. Included is a description of the instrument characteristics and principle of operation as well as a comparison of measured and theoretical accuracy limits.