Highly tunable ultra-narrow-resonances with optical nano-antenna phased arrays in the infrared

TL;DR

This paper demonstrates highly tunable, ultra-narrow plasmonic resonances in 2D nanorod arrays with high Q-factors, suitable for sensing and nonlinear photonics, achieved through material and geometric tuning.

Contribution

It introduces a method to achieve high-Q plasmonic resonances in 2D nanorod arrays with tunability across infrared to terahertz frequencies, enhancing sensing and photonic applications.

Findings

High-Q resonances vary from near-infrared to terahertz

Resonances are tunable via material, length, and polarization

High Purcell factor and environmental stability for sensing

Abstract

We report our recent development in pursuing high Quality-Factor (high-Q factor) plasmonic resonances, with vertically aligned two dimensional (2-D) periodic nanorod arrays. The 2-D vertically aligned nano-antenna array can have high-Q resonances varying arbitrarily from near infrared to terahertz regime, as the antenna resonances of the nanorod are highly tunable through material properties, the length of the nanorod, and the orthogonal polarization direction with respect to the lattice surface,. The high-Q in combination with the small optical mode volume gives a very high Purcell factor, which could potentially be applied to various enhanced nonlinear photonics or optoelectronic devices. The 'hot spots' around the nanorods can be easily harvested as no index-matching is necessary. The resonances maintain their high-Q factor with the change of the environmental refractive index, which is of great interest for molecular sensing.