Modulation of plasmonic relaxation damping by surface phonons

Abstract

We experimentally study the effect of amplitude-varying surface acoustic waves on a localized surface plasmon (LSP), which unveils exceptional properties of plasmon-phonon interaction with promising applications in future tunable photonic devices. Gold nanoparticles are deposited on X-cut LiNbO 3 to generate plasmonic oscillation, and an interdigital transducer is fabricated to create surface acoustic wave pulses. The interaction between an amplitude-varying mechanical wave and a plasmonic oscillation affects different plasmon dynamics and relaxation gradients, leading to a systematic change in LSP absorption. We also demonstrated the effect of polarized light on the device, providing a unique characteristic to explore the manipulation process effectively.