Abstract
Metallic bowtie nanoantennas should provide optical fields that are confined to spatial scales far below the diffraction limit. To improve the mismatch between optical wavelengths and nanoscale objects, we have lithographically fabricated Au bowties with lengths and gaps of tens of nm. Using two-photon-excited photoluminescence of Au, the local intensity enhancement factor relative to that for the incident diffraction-limited beam has been experimentally determined for the first time. Enhancements occur for 20 nm gap bowties, in good agreement with theoretical simulations.
- Received 16 September 2004
DOI:https://doi.org/10.1103/PhysRevLett.94.017402
©2005 American Physical Society