By considering waves that propagate out of the transverse plane, we show that common high-index materials (e.g., GaAs) with a two-dimensional array of air holes can act in some ways as three-dimensional photonic band-gap structures. In particular, we describe a dielectric quasi-metal that ref lects all propagating light incident from free space.
P. J. Roberts, T. A. Birks, P. St. J. Russell, T. J. Shepherd, and D. M. Atkin, "Two-dimensional photonic band-gap structures as quasi-metals," Opt. Lett. 21, 507-509 (1996)