4. Electronic speckle interferometry or TV-holography

4.1 Principle

Here again, the commercial term TV-holography has become commonplace. Anglo-Saxons still sometimes use the term ESPI (Electronic Speckle Pattern Interferometry).

This is in fact a modified Michelson interferometer, in which one of the mirrors is replaced by the object to be studied. As in the previous case, the photosensitive medium can be a CCD camera if you wish to quantify the results and/or work in real time (figure 12 ).