Graphene, a one-atom-thick layer of carbon, has attracted enormous attention in diverse areas of applied and fundamental physics. Due to its unique crystal structure, charge carriers have an effective mass of zero and a very high mobility, even at room temperature. While graphene-based devices have an enormous potential for high-speed electronics, graphene has recently been recognized as a photonic material for novel optoelectronic applications.Interestingly, graphene is also a promising host material for light that is confined to nanoscale dimensions, more than 100 times below the diffraction limit. Due to its ultra-small thickness and extremely high purity, graphene can support strongly confined propagating light fields coupled to the charge carriers in the material: surface plasmons. The properties of these plasmons are controllable by electrostatic gates, holding promise for in-situ tunability of light-matter interactions at a length scale far below the wavelength.This project will experimentally investigate the new and virtually unexplored field of graphene surface plasmonics, and combine this with other appealing properties of graphene to demonstrate the unique potential of carbon-based nano-optoelectronics. The aim is to explore the limits of unprecedented light concentration, manipulation and detection at the nanoscale, to dramatically intensify nonlinear interactions between photons towards the quantum regime, and to reveal the subtle effects of cavity quantum electrodynamics on graphene-emitter systems. This research will reveal the far-reaching potential of a single sheet of carbon atoms as a host for light and electrons at the nanoscale, with prospects for novel nanoscale optical circuits and detectors, nano-optomechanical systems and tunable artificial quantum emitters.