PROCESS AND DEVICE FOR THE DIFFERENTIAL MEASUREMENT OF REFRACTION INDEXES AND USE THEREOF

摘要

Process for measurement of the difference between the refraction indexes of two media, each crossed by a light beam. Said beams are capable of generating an interference figure consisting of fringes, the shift of the latter being measured. According to the invention, a single means is used to detect the shift of said fringes. A phase modulation is applied to at least one of the beams and the modulation is controlled so as to shift said fringes.