Optical counterpart of a Foucault pendulum

The twin beam vortex interferometer with a phase-conjugating mirror in a rotating reference frame is analyzed. The circular motion of the interference pattern occurs due to the exchange of angular momenta between photons and the interferometer. Using the concept of the ideal phase-conjugating mirror, it is shown that the motion of the heli-cal interference pattern of interacting vortex photons with topological charge 2 may be used for detection of slow rotations. The higher density of interference fringes may improve sensitivity by a factor containing 22 compared to conventional Michelson interferometry. (c) 2023 Optica Publishing Group