Georges Sagnac was a French physicist best known for his work in the field of optics and his experiments related to the theory of relativity. Born on June 14, 1869, Sagnac is particularly famous for the Sagnac effect, which he demonstrated in 1913. The Sagnac effect involves the observation that a rotating interferometer produces a measurable phase shift in light beams that travel in opposite directions around a closed loop.
