Twyman-Green interferometer

A Twyman-Green interferometer is a variant of the Michelson interferometer principally used to test optical components. The setup of the Twyman-Green interferometer is similar to that of the Michelson interferometer (cf. same for a picture of the setup). There are two differences between the Michelson and Twyman-Green interferometers. First, the fixed mirror in the Michelson interferometer is rotatable in the Twyman-Green interferometer, and second, while the light source is usually an extended source (although it can also be a laser) in a Michelson interferometer, the light source is always a point-like source in the Twyman-Green interferometer.

The rotation of one mirror results in straight fringes appearing in the interference pattern, a fringing which is used to test the quality of optical components by observing changes in the fringe pattern when the component is placed in one arm of the interferometer.


* University of Tennessee Modern Optics course

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