Tunneling-induced temporary light trapping in negative-index-clad slab waveguide

We propose a waveguide structure in which the tunneling or leakage of guided light results in a type of temporary light trapping. This can be possible by the adoption of a thin clad composed of a negative-refractive-index medium, which, with a conventional dielectric core, produces a backward Goos-Hanchen shift whose amount is critically dependent on the thickness of the clad. At an appropriate clad thickness, the forward propagation of the light in the core can be completely compensated by the backward Goos-Hanchen shift; thus, we can make the net propagation distance of the light exactly zero, i.e., we can trap the light. This trap is temporary since the trapped light tunnels out completely through the thin clad after a short time.