Twisted Cavity Resonators of Anyon Rotational Symmetry with Electromagnetic Helicity

Twisting the conducting boundary conditions of an electromagnetic cavity with an equilateral triangle cross-section generates eigenmodes with electromagnetic helicity - a result of the coupling of previously degenerate TE and TM modes. This can be interpreted as an emergence of magnetoelectricity, which produces a confirmable shift in resonant mode frequency. By dynamically controlling the twist angle of a cavity resonator, we demonstrate real-time, macroscopic manipulation of electromagnetic helicity and mode frequency.