Sagnacinterferométer

The Sagnac interferometer is an optical instrument that utilizes the Sagnac effect to detect rotation. Invented by French physicist Georges Sagnac in 1913, it consists of a light source, a beam splitter, two mirrors, and a detector. Light from the source is split into two beams by the beam splitter. These beams travel in opposite directions around a closed optical path formed by the mirrors. When the interferometer is stationary, the two beams recombine at the beam splitter and interfere with each other. However, if the interferometer is rotated, the path length for one beam will appear longer, and for the other, shorter, due to the rotation. This difference in path length causes a phase shift between the recombined beams, which is detected as a change in the interference pattern. The magnitude of this phase shift is directly proportional to the angular velocity of the rotation and the area enclosed by the light path. Sagnac interferometers are highly sensitive and are widely used in inertial navigation systems, such as those found in aircraft and spacecraft, as well as in scientific research to measure various rotational phenomena. They are known for their robustness and stability.