Nonlinear thermoplasmonics in photoexcited graphene nanoribbons

Nonlinear optical phenomena enable the control of light by light both temporally and spectrally, and therefore represent a crucial resource for emerging integrated photonic and quantum optical technologies [1,2]. Graphene is an excellent material in this context due to its large intrinsic nonlinear optical response. Additionally, the combination of graphene's linear electronic bands and atomic thickness results in plasmon resonances with high sensitivity to charge carrier doping, enabling the electrical tunability of plasmon resonances at terahertz (THz) or infrared (IR) frequencies. However, pushing graphene plasmon resonances to the near-IR and visible spectral regime requires high charge doping levels that are difficult to achieve via electrostatic gating, or patterning on ~10 nm length scales, where quantum finite-size effects play an important role [3,4].