Electromechanically Tunable Suspended Optical Nano-antenna

TL;DR

This paper presents a suspended optical nano-antenna whose resonance can be precisely tuned via electromechanical control, enabling large bandwidth nanoelectromechanical systems with potential applications in sensing and active plasmonics.

Contribution

It introduces a novel suspended two-wire plasmonic nano-antenna that can be electromechanically tuned without disturbing its resonance, advancing nanoelectromechanical system capabilities.

Findings

Resonance wavelength can be reversibly tuned by voltage.

The nano-antenna acts as a nano-electrometer.

Potential for large bandwidth optical NEMS.

Abstract

Coupling mechanical degrees of freedom with plasmonic resonances has potential applications in optomechanics, sensing, and active plasmonics. Here we demonstrate a suspended two-wire plasmonic nano-antenna acting like a nano-electrometer. The antenna wires are supported and electrically connected via thin leads without disturbing the antenna resonance. As a voltage is applied, equal charges are induced on both antenna wires. The resulting equilibrium between the repulsive Coulomb force and the restoring elastic bending force enables us to precisely control the gap size. As a result the resonance wavelength and the field enhancement of the suspended optical nano-antenna (SONA) can be reversibly tuned. Our experiments highlight the potential to realize large bandwidth optical nanoelectromechanical systems (NEMS).