Spectral exploration of asymmetric bowtie nanoantennas

Abstract

Bowtie nanoantennas are nanostructures widely used in the field of optical sensing. At present, most of the bowtie nanoantennas are symmetrical structures. Their spectra are dominated by dipolar plasmonic modes. Usually, asymmetries caused by statistical variation in the nanofabrication process are neglected. In this work we have designed, fabricated and characterized nanostructures with varying degrees of asymmetry. The optical behavior was compared with that of symmetrical structures of corresponding dimensions. This study gives a deeper understanding of how asymmetry affects the optical performance of nanoantennas, and how it can be harnessed to introduce additional degrees of freedom, providing extended design ideas for nanosensors.

Keywords

• Gold nanoantenna
• Asymmetric bowtie structure
• Tunable resonance
• Spectral linewidth
• Plasmonics
• Electron beam lithography