Application of holographic optical elements in active interferometers for nondestructive testing

Active interferometers can continuously adapt themselves to the change of measuring conditions and environment. This type of interferometers is investigated in the article. As a major feature, the wave fronts of the interferometer are formed by different holographic optical elements. Using this technique the fringe density at highly deformed points can be decreased or different components of the complicated fringe pattern can be removed which results in increase of the sensitivity and leads to easier evaluation of the fringe pattern. Selected applications in speckle metrology and digital holography are shown demonstrating applications of computer generated and classical types of HOE-s.