Modulation of a surface plasmon-polariton resonance by sub-terahertz diffracted coherent phonons

TL;DR

This paper demonstrates high-frequency modulation of surface plasmon-polariton resonance using sub-terahertz coherent phonons interacting with a specially designed gold nanostructure, enabling efficient control of light reflectivity.

Contribution

It introduces a novel method of modulating plasmon-polariton resonance via sub-THz phonons in a nanostructure with combined plasmon and phonon resonances.

Findings

Achieved up to 110 GHz modulation of reflectivity.

Designed a nanostructure with coupled plasmon and phonon resonances.

Theoretical analysis links modulation to slit width variations at phonon frequencies.

Abstract

Coherent sub-THz phonons incident on a gold grating that is deposited on a dielectric substrate undergo diffraction and thereby induce an alteration of the surface plasmon-polariton resonance. This results in efficient high-frequency modulation (up to 110 GHz) of the structure's reflectivity for visible light in the vicinity of the plasmon-polariton resonance. High modulation efficiency is achieved by designing a periodic nanostructure which provides both plasmon-polariton and phonon resonances. Our theoretical analysis shows that the dynamical alteration of the plasmon-polariton resonance is governed by modulation of the slit widths within the grating at the frequencies of higher-order phonon resonances.