Half-period Aharonov-Bohm oscillations in disordered rotating optical ring cavities

There exists an analogy between Maxwell equations in a rotating frame and Schr\"odinger equation for a charged particle in the presence of a magnetic field. We exploit this analogy to point out that electromagnetic phenomena in the rotating frame, under appropriate conditions, can exhibit periodicity with respect to the angular velocity of rotation. In particular, in disordered ring cavities one finds the optical analog of the Al'tshuler-Aronov-Spivak effect well known in mesoscopic physics of disordered metals.