Shearing Interferometers

: SIS 078

: Shearing Interferometers can be used to determine if a coherent beam of light is collimated. The design consists of a wedged optical flat mounted at 45° and a diffuser plate with a ruled reference line down the middle. These interferometers are designed to provide qualitative analysis of a beam's collimation.

: shearing interferometer is an extremely simple means to observe interference and to use this phenomenon to test the collimation of light beams, especially from laser sources which have a coherence length which is usually a lot longer than the thickness of the shear plate (see graphics) so that the basic condition for interference is fulfilled.