An apparatus comprises a thin film metallic layer, a first dielectric layer arranged on a first side of said thin film metallic layer and having a first index of refraction, a second dielectric layer arranged on the opposite side of said thin film metallic layer from said first dielectric layer, a third dielectric layer arranged on the first side of the thin film metallic layer adjacent to the first dielectric layer and having a second index of refraction that is lower than the first index of refraction, and wherein the thin film metallic layer, the first dielectric layer and the third dielectric layer are arranged to focus plasmon waves induced at an interface between the thin film metallic layer and the third dielectric layer.