Stimulated Brillouin Scattering and Related Processes in Graphene Waveguides

We present the latest findings of our study of Stimulated Brillouin scattering (SBS) and related processes (such as Raman scattering) in waveguide involving graphene.

Graphene is considered an interesting material for photonics research, mostly because of its peculiar electronic dispersion relation. Its linear energy-momentum relationship results in a number of optical properties. Firstly, graphene is an astonishingly strong absorber, e.g. when placed atop am integrated photonic waveguide. This can be interpreted as a effective scattering cross that exceeds the Angstrom-thin geometric thickness by orders of magnitude. Therefore, variations to the optical properties of graphene (whether induced by a local strain field or some other mechanism) can be expected to lead to significant scattering despite it being a single layer of atoms. Secondly, graphene supports highly localized plasmon polaritons. Their localization length, which is two to three orders of magnitude smaller than the vacuum wave length of light, leads to very significant field enhancements, boosting any nonlinear interaction. Finally, graphene has the reputation of being a highly nonlinear optical material to begin with. Therefore, there is good reason to believe that a nonlinear process such as SBS could benefit significantly from a clever addition of graphene to the overall system. Here, we present our research on the topic. We give an overview of the main challenges such as loss and wavelength range and provide estimates for the achievable gain figures. We will comment on the feasibility of such nonlinearities, both for infrared and THz optics and especially for the characterization of the fundamental material properties of graphene monolayers.