Optimizing Electromagnetic Hotspots in Plasmonic Bowtie Nanoantennae

Stephanie Dodson (1) , Mohamed Haggui (2) , Renaud Bachelot (2) , Jerome Plain (2) , Shuzhou Li (1) , Qihua Xiong (1)

1 Nanyang Technological University [Singapour]
2 LNIO - Laboratoire de Nanotechnologie et d'Instrumentation Optique

Sensitivity is a key factor in the improvement of nanoparticle-based biosensors. Bowtie nanoantennae have shown high sensitivity for both surface-enhanced Raman scattering (SERS)- and localized surface plasmon resonance (LSPR)-based biosensing. In this work, optical bowtie nanoantennae with varying geometries were simulated, fabricated, and characterized. We successfully fabricated sub-5 nm gaps between prisms. The gap between prisms, the prism size, and the radius of curvature of the prism corners were characterized for their effects on the optical and electromagnetic properties. Bowties were characterized using LSPR, SERS, and photochemical near-field imaging. The results indicate that the radius of curvature of the prism corners has an important effect on the SERS abilities of a nanoparticle array. The trends described herein can be utilized to intelligently design highly sensitive SERS and LSPR biosensing substrates.

Keywords: plasmonics; surface-enhanced raman spectroscopy (SERS); localized surface plasmon resonance (LSPR); optical nanoantenna; discrete dipole approximation (DDA)

Domains: Physics [physics]; Physics [physics]; Optics [physics.optics]; Engineering Sciences [physics]; Micro and nanotechnologies/Microelectronics

Stephanie Dodson, Mohamed Haggui, Renaud Bachelot, Jerome Plain, Shuzhou Li, et al.. Optimizing Electromagnetic Hotspots in Plasmonic Bowtie Nanoantennae. Journal of Physical Chemistry Letters, 2013, 4 (3), pp.496-501. ⟨10.1021/jz302018x⟩. ⟨hal-02440676⟩