# Tunable Plasmonic Bandwidth Broadening via DC Electrical Bias

## TL;DR

This paper shows how applying a direct current electric field can tune and broaden the bandwidth of nanoresonators, enabling dynamic control of their optical properties.

## Contribution

A tunable method for plasmonic bandwidth broadening using a DC electric field, enabled by charge redistribution on metal surfaces.

## Key findings

- Applying a DC electric field redistributes surface charges, inducing charge asymmetry on metal surfaces.
- The induced charge asymmetry splits plasmonic modes, leading to bandwidth broadening.
- Optical response can be finely controlled by adjusting the amplitude and direction of the bias field.

## Abstract

The ability to broaden the bandwidth of nanodevices holds significant promise for applications in modern science and technology. In this work, we demonstrate a tunable approach to the bandwidth modulation of nanoresonators by applying a direct current electric field. Quantum hydrodynamic theory reveals that the biased electric field redistributes surface charges, inducing positively and negatively charged regions on the metal surface. This charge asymmetry splits the plasmonic modes, resulting in bandwidth broadening. The optical response can be finely tuned by varying the amplitude and polarization direction of the bias field. This mechanism offers a versatile strategy for developing nanodevices, including metasurfaces with dynamically adjustable bandwidths.