MODEL RELEASED. Laser interferometer. Researcher operating a laser interferometer. The red beams of the laser are seen reflecting from mirrors as well as crossing at lower centre. The basic principle of an interferometer detects a physical change by the interference between two waves travelling on two different paths. In this case the interference is for laser light, though ordinary light, sound and radio waves can also be used. Numerous uses of interferometry include new holographic computer memories and the distance and size of astronomical objects. The goggles worn by the researcher protect him from being blinded by the intense energy of the laser beams.