The use of a fibre-optic reference beam in a focused image holographic interferometer

Holographic interferograms recorded in the image plane of an optical system may be referenced by a beam transmitted through an incoherent fibre-optic bundle. In such a system the object to reference beam intensity ratio is non-critical, and path-length matching is easily achieved with commercial push fit connectors. Such an interferometer gives the user greater flexibility and can be used in a wide range of environments.