Vacuum-excited surface plasmon polaritons

TL;DR

This paper explores how surface plasmon polaritons (SPPs) can be generated from vacuum through time-dependent dielectric and magnetic variations at metal interfaces, offering a new approach to observing quantum vacuum effects.

Contribution

It introduces a theoretical framework for vacuum-excited SPPs via a generalized Lorenz gauge and suggests experimental setups to detect these excitations, extending dynamical Casimir effect concepts.

Findings

Vacuum excited SPPs can be generated with magnitudes comparable to photon creation rates.

Detection of SPPs does not require sealed cavities and can use simple phase matching techniques.

TM branch SPPs are less affected by detuning and attenuation compared to TE photons.

Abstract

We separate Maxwell's equations for background media that allow for both electric and magnetic time-dependence in a generalized Lorenz gauge. In a process analogous to the dynamical Casimir effect (DCE) we discuss how surface plasmon polaritons (SPP)s can be created out of vacuum, via the time-dependent variation of a dielectric and magnetic insulator at a metal interface for TM and TE branches, respectively. We suggest how to extend currently proposed DCE experiments to set up and detect these excitations. Numerical simulations (without any approximation) indicate that vacuum excited SPPs can be of a similar magnitude to the photon creation rate in such experiments. Potential benefits of detecting vacuum excited SPPs, as opposed to DCE photons, are that parametric enhancement does not require a sealed cavity in the axial direction and the detection apparatus might be able to use simple phase matching techniques. For the case of constant permeability, $\mu$, TM branch SPPs and photons do not suffer from detuning and attenuation like TE photons.