# Stimulated plasmon polariton scattering

## TL;DR

This paper introduces stimulated plasmon polariton scattering (SPPS), a nonlinear resonant scattering technique that enables excitation, amplification, and detection of 2D plasmon and phonon polaritons across the THz range using simple optical components.

## Contribution

It proposes a new nonlinear scattering method, SPPS, for studying 2D polaritons, with theoretical analysis showing significantly higher power gains than existing techniques.

## Key findings

- SPPS allows excitation and detection of 2D polaritons in the THz range.
- SPPS power gains surpass those of on-chip SBS by at least an order of magnitude.
- The method opens new avenues for THz spectroscopy and 2D material research.

## Abstract

The plasmon and phonon polaritons of two-dimensional (2d) and van-der-Waals materials have recently gained substantial interest. Unfortunately, they are notoriously hard to observe in linear response because of their strong confinement, low frequency and longitudinal mode symmetry. Here, we propose a fundamentally new approach of harnessing nonlinear resonant scattering that we call stimulated plasmon polariton scattering (SPPS) in analogy to the opto-acoustic stimulated Brillouin scattering (SBS). We show that SPS allows to excite, amplify and detect 2d plasmon and phonon polaritons all across the THz-range while requiring only optical components in the near-IR or visible range. We present a coupled-mode theory framework for SPS and based on this find that SPS power gains exceed the very top gains observed in on-chip SBS by at least an order of magnitude. This opens exciting new possibilities to fundamental studies of 2d materials and will help closing the THz gap in spectrocopy and information technology.