Artificial Gauge Field for Photons in Coupled Cavity Arrays

We propose and characterize solid-state photonic structures where light experiences an artificial gauge field. A suitable coupling of the propagation and polarization degrees of freedom introduces a geometrical phase for photons tunneling between adjacent sites of a coupled cavity array. We then discuss the feasibility of observing strong gauge field effects in the optical spectra of realistic systems, including the Hofstadter butterfly spectrum.