Etymology

Named after French physicist Georges Sagnac.

Noun

Sagnac effect (plural Sagnac effects)Category:English lemmas#SAGNACEFFECTCategory:English nouns#SAGNACEFFECTCategory:English countable nouns#SAGNACEFFECTCategory:English multiword terms#SAGNACEFFECTCategory:English entries with incorrect language header#SAGNACEFFECTCategory:Pages with entries#SAGNAC%20EFFECTCategory:Pages with 1 entry#SAGNAC%20EFFECT

1. A phenomenon encountered in interferometry that is elicited by rotation. The Sagnac effect manifests itself in a setup called a ring interferometer. A beam of light is split and the two beams are made to follow the same path but in opposite directions. To act as a ring the trajectory must enclose an area. On return to the point of entry the two light beams are allowed to exit the ring and undergo interference. The relative phases of the two exiting beams, and thus the position of the interference fringes, are shifted according to the angular velocity of the apparatus.