The fractal hypothesis and anomalous di usion

A method of testing an object in which a beam of laser radiation is split into two portions, the object is illuminated with a first beam portion and is caused to vibrate, one of said beam portions is phase modulated in predetermined phase relationship with the object vibration and the radiation scattered from the blade is caused to fall upon a photographic emulsion together with the second reference beam portion to form a hologram. The invention also comprises apparatus for carrying out this method.