Enhanced Raman Scattering of Graphene using Double Resonance in Silicon Photonic Crystal Nanocavities

摘要

We demonstrate enhancements of Raman scattering from grapheneon L3 photonic crystals (Fig. 1a) using double resonances, whichoriginate from simultaneous enhancements by a localized guided modeand a cavity mode . By adjusting the photonic crystal cavityparameters, the double resonance can be tuned to the G’ Ramanscattering. Excitation wavelength dependence measurements show alarge Raman peak enhancement when the excitation and emissionwavelengths meet the double resonance condition (Fig. 1b).Furthermore, spatial imaging measurements are performed to confirmthat the enhancement is localized at the cavity, and we find that theenhanced Raman intensity is 60 times larger compared to theon-substrate Raman signal. The observed cavity enhancement ofRaman scattering opens up new possibilities for the development ofgraphene-based light sources for silicon photonics.