Remotely coupled surface plasmons in a metal/insulator/Si structure perforated with periodic square hole arrays

Abstract

The zero-order transmission of radiation through a metal/dielectric structure perforated with square hole arrays is strongly enhanced when incident light resonates with surface plasmons (SPs). Surprisingly, when a metal/dielectric double layer, such as Ag/SiO2, is fabricated on a silicon substrate, the Ag/Si SP mode by coupling Ag and Si across the intermediate dielectric film has been found. It is named the remotely coupled surface plasmon. The transmission intensity is investigated as a function of the intermediate SiO2 thickness. The coupling lengths between Ag and Si in order to form the Ag/Si SP mode are determined as well, and they turn out to be 500 and 130 nm for couplings through air and a SiO2 layer, respectively. © 2006 American Institute of Physics.