Abstract

Localized surface plasma is a well-known phenomenon in plasmonics. Due to the interaction with high-frequency electromagnetic fields, electromagnetic coupling could be produced in ordered metal structure array. One of the famous shape arrays is the periodic bowtie antennas, in which two noble metal triangles face tip-to-tip and are separated by a very small gap. Very strong electromagnetic field enhancement can occur between two closely spaced metal triangles, called “nanogap effect [1].” This large enhancement could be used as a tool to enable the single molecule detection via surface-enhanced Raman scattering (SERS). “Free standing” is a new and powerful way to enhance the localized surface plasmon [1]. In this study, we used the finite-difference time-domain (FDTD) method to study the relationship between the surface plasmon resonance and the different geometrical structures.

© 2013 Japan Society of Applied Physics, Optical Society of America