Dual reference beam holographic interferometry
Holographic interferometry - Principles

This technique can be used to calculate micrometric displacements at any point on an object's surface, based on its interferometric hologram, and to visualize them globally via a computer representation in pseudo-relief or false color. It can be used with continuous emission lasers in the laboratory, or with pulsed lasers in industrial environments, such as vibration analysis in the automotive and aerospace industries.

Structures with a surface area of several dozen square meters can thus be studied.

Let's illustrate the operating principle in the case of double exposure