Effects of dielectric substrate properties for optical phenomena in a nanoscale ridge aperture

Abstract

In this paper, we show that the increase in power throughput is dependent on the thickness and the relative permittivity of the dielectric substrate in the aperture-on-dielectric-substrate configuration. We also show that, similar to a metal nanoparticle, an increase in the medium dielectric constant results in a red-shift in the plasmon resonance of a nanoscale ridge aperture. These results, which are verified by a numerical analysis, provide a new understanding of the phenomenon of surface-plasmon-enhanced transmission. We demonstrate that the red-shifted wavelength and dielectric properties can compensate for the optical loss due to plasmon red-shift. In addition, the dielectric substrate layer behaves like a Fabry–Pérot optical resonator, resulting in coherent constructive interference. The simulation results show that the |E|2 intensity of the triangular aperture is ∼200% greater when this dielectric effect and red-shift resonance are considered.