4. Application to soap film dynamics

Thin films are of fundamental interest for the study of turbulence effects, but also for applications such as cell membranes in biology and foams in industry. Various optical methods have been used to study these films, using two-wave interferometers for transmission , reflection and absorption in the infrared range . However, these techniques can only probe the film at a single point, and do not provide access to the thickness gradient, for example. The Jamin-Fabry-Perot interferometer is therefore the ideal tool for such a study.

A soap film can easily be made using a solution containing commercial dishwashing liquid, glycerine and water. Simply dip a horizontal bar into the solution, then gently pull it upwards. The result is a vertical film of soap . Typical film sizes are around 10 cm...