Long lived surface plasmons on the interface of a metal and a photonic time-crystal

TL;DR

This paper predicts and simulates long-lived surface plasmon polaritons at a metal and photonic time-crystal interface, revealing unique dispersion properties and potential to mitigate plasmonic losses.

Contribution

It introduces the concept of surface plasmons on a metal and photonic time-crystal interface, with detailed dispersion analysis and simulation of their formation and evolution.

Findings

Multi-branched dispersion curves with momentum gaps

High and low group velocity modes at short wavelengths

Potential to overcome plasmonic losses

Abstract

We predict the existence of surface plasmons polaritons at the interface between a metal and a periodically modulated dielectric medium, and find an unusual multi-branched dispersion curve of surface and bulk modes. The branches are separated by momentum gaps indicating intense amplification of modes, and display high and low group velocity ranging from zero to infinity at short wavelengths. We simulate how these SPP modes are formed by launching a properly engineered laser beam onto the metallic interface and examine their space-time evolution. The amplification of the surface plasmons at the interface with a photonic time-crystal offers a path to overcome plasmonic losses, which have been a major challenge in plasmonics.