Enhanced Raman scattering of graphene using double resonance in silicon photonic crystal nanocavities

TL;DR

This paper demonstrates that double resonance in silicon photonic crystal nanocavities can significantly enhance Raman scattering from graphene, achieving up to 60-fold increase and enabling new graphene-based photonic devices.

Contribution

The study introduces a method to enhance graphene Raman signals using tunable double resonance in photonic crystal nanocavities, a novel approach for light-matter interaction enhancement.

Findings

Raman signal enhanced up to 60 times at double resonance

Enhancement localized at the photonic crystal cavity

Tunable double resonance aligns with G' Raman scattering

Abstract

We demonstrate enhancements of Raman scattering from graphene on two-dimensional photonic crystals using double resonances, which originate from simultaneous enhancements by a localized guided mode and a cavity mode. By adjusting the photonic crystal cavity parameters, the double resonance can be tuned to the G' Raman scattering. Excitation wavelength dependence measurements show a large Raman peak enhancement when the excitation and emission wavelengths meet the double resonance condition. Furthermore, spatial imaging measurements are performed to confirm that the enhancement is localized at the cavity, and we find that the enhanced Raman intensity is 60 times larger compared to the on-substrate Raman signal. The observed cavity enhancement of Raman scattering opens up new possibilities for the development of graphene-based light sources for silicon photonics.