Engineering effective optical gauge fields in anisotropic Fabry-Pérot cavities.

Gauge fields, fundamental to the study of classical electromagnetism and the standard model of particle physics, have recently found significant applications in optics and photonics. Here, we investigate the emergence of effective optical gauge fields in anisotropic Fabry-Pérot cavities, resulting from the coupling between cavity modes with different polarization. As an example, the intrinsic biaxial anisotropy of the intracavity material induces an effective optical gauge field, manifesting as a transition from the optical spin Hall effect to Zitterbewegung of light at different frequencies. The simulation results confirm that the wave packet dynamics, along with the evolution of pseudo-spins driven by anisotropy, can be comprehensively understood using effective optical gauge field theory around unique band crossings. A kind of metamaterial embedded in the Fabry-Pérot cavity is proposed and implemented to realize biaxial anisotropy using effective medium theory, as verified by simulation results and experimental measurements. The emergent effective optical gauge field in a biaxial anisotropic cavity may offer what we believe to be new insights into manipulating light trajectories and designing advanced polarization-sensitive optical devices.