Abstract
The enhancement of the electromagnetic field is described for nanoscale metallic “bowtie” antennas, consisting of two opposing tip-to-tip Au nanotriangles separated by a gap, through simulation and experiment. Currents, field distributions, and scattering efficiencies in the antennas at optical wavelengths are obtained from finite-difference time-domain (FDTD) simulations using realistic wavelength-dependent dielectric constants. The experimentally measured resonant wavelengths and intensity enhancements from individual bowtie antennas are in excellent agreement with the FDTD simulations. A simple physical model based on current distribution in the antennas is presented to understand the variation in resonant wavelength with gap and explain the basis for the field enhancement.
- Received 12 May 2005
DOI:https://doi.org/10.1103/PhysRevB.72.165409
©2005 American Physical Society