Transmission Enhancement of Light through a Metallic Nano-slit withPeriodic Metallic Nano-strips

摘要

The study of the transmission properties of subwavelength apertures has become a very active area of research inelectromagnetism. It is generally accepted that structuring the input surface of the metal film by periodic corrugations isvery effective in the process of transmission enhancement through single apertures. Here instead of periodiccorrugations, we propose to use periodic nano-strips placed before the input surface of the metal film to enhance thetransmission of light through a nano-slit milled in the film. Influences of the structural parameters of periodic nano-stripson the transmission enhancement are investigated. The transmission efficiency through a 25nm-width silver nano-slit canbe boosted to be = 164 when six pairs of nano-strips are placed 50nm distant away from the incident surface of thesilver film at λ_0 = 1μm, which is originally η = 7.8 without any strips. This indicates that a large part of the incident lightcan be transformed into the localized guided wave with strong intensity, and then more light can flow through thenano-slit. We emphasize that periodic nano-strips can serve as an efficient receiving antenna to harvest light into thenano-slit.