Photon band structure in a rotating fiber-optic ring resonator

In a rotating fiber-optic ring resonator, interference between elastically scattered waves has been predicted to establish a photon band structure, Including forbidden frequency zones (“bandgaps”)[1]. The elastic scattering couples counterpropagating light waves, thus lifting the degeneracy of the eigenmodes of the resonator and transforming crossings into anticrossings. This phenomenon is closely related to the Aharanov-Bohm flux-periodic effects in small normal-metal rings, where the magnetic flux encompassed by the ring introduces a round-trip phase difference between counterpropagating electronic waves[2]. In the optical case the role of the magnetic flux is played by the product of rotation rate and ring area, i.e. the rotation flux, that introduces such phase difference via the Sagnac-effect. Whereas in the electronic case the magnetic flux period equals h/e, the rotation flux period for the optical case can be written as h/mph, with mph the photon mass hν/c2