Holographic interferometry of diffusely reflecting objects with a surface microrelief varying in time

A description is given of a method and apparatus suitable for holographic interference recording of deformation of an object in the case when its surface microrelief changes between exposures. If visible laser radiation is used, the method makes it possible to carry out an interferometric comparison of two states of an object at some controlled equivalent wavelength which is long compared with the changes in the surface microrelief but short compared with the deformations of the object. Some experimental results are reported.