Plasmon−Plasmon Interactions and Radiative Damping of Plasmons in Nanostructured Graphene

While graphene absorbs only 2.3% in the mid infra red (IR) spectral region, graphene plasmons have much stronger absorption in the far IR. Plasmons tunability by the external electric fields and by the spatial confinment offer a promising platform for opto-electronic and sensor applications. In this work [1], we demonstrate both theoretically and experimentally that the plasmon−plasmon and plasmon−radiation interactions modify strongly the plasmon resonance energy, radiative damping, and oscillator strength in graphene nanoribbon arrays. Even for the moderate filling factors of about 50%, plasmon radiative lifetime reduces to a ps time scale from a convetional ns time scale in the isolated graphene nanoribbon. We find scaling of plasmons with respect to the graphene doping level and filling factor, which both modify the strength of the long-range Coulomb and plamson-radiative interactions. The surprisingly large plasmon energy shift and radiative damping significantly affect the graphene-based plasmonic device performance.
[1] Vyacheslav Semenenko, Simone Schuler, Alba Centeno, Amaia Zurutuza, Thomas Mueller, and Vasili Perebeinos, ACS Photonics 5, 3459–3465, 2018.