Phonon-mediated dark to bright plasmon conversion

TL;DR

This paper introduces a quantum model for nanophotonic systems where strong interactions between quantum-confined plasmons and optical phonons occur, revealing a new oscillator strength transfer mechanism.

Contribution

It develops a quantum model that extends beyond the classical Drude-Lorentz approach, explaining dark to bright plasmon conversion in symmetry-broken potentials.

Findings

Identifies failure of classical models in certain quantum regimes

Proposes a new quantum model for plasmon-phonon interactions

Reveals a mechanism for oscillator strength transfer between modes

Abstract

The optical response of a matter excitation embedded in nanophotonic devices is commonly described by the Drude-Lorentz model. Here, we demonstrate that this widely used approach fails in the case where quantum-confined plasmons of a two-dimensional electron gas interact strongly with optical phonons. We propose a new quantum model which contains the semiclassical Drude-Lorentz one for simple electronic potentials, but predicts very different results in symmetry-broken potentials. We unveil a new mechanism for the oscillator strength transfer between bright phonon-polariton and dark plasmon modes, enabling thus new quantum degrees of freedom for designing the optical response of nanostructures.