This Rapid Communication reports on the modulation of the position and linewidth of the $G$ and $2D$ Raman bands for monolayer graphene through coupling to surface plasmon polaritons (SPPs). It is shown that gold nanoresonators tuned to the graphene Stokes emission frequency, not the laser pump, broaden the $G$ and $2D$ peaks and shift them to lower wave numbers, in addition to enhancing the Raman scattering cross section. The variation of the band displacement and broadening with the SPPs’ frequency demonstrates a strongly dispersive phenomenon, ruling out chemical, mechanical, and thermal mechanisms. It is believed that strong graphene-SPP coupling is responsible for the frequency pulling and line-shape broadening.

• Received 24 February 2015
• Revised 3 March 2015

DOI:https://doi.org/10.1103/PhysRevB.91.201408

Source: http://link.aps.org/doi/10.1103/PhysRevB.91.201408