(Feb 6th) Electronically Tunable Mid-infrared Light Manipulation and Generation using Graphene Plasmons

Abstract: Graphene is a monolayer of carbon atoms constructing a two-dimensional honeycomb structure, and it has an excellent carrier mobility and a very high thermal conductivity. Recently, graphene based optical modulators and phase shifters have emerged as an area of intense research partly due to the ability of confined graphene plasmonic resonances to create a strong electrostatic response at THz to mid-IR frequencies. Additionally, the high confinement factor of graphene plasmons allow for the creation of highly miniaturize and active optical elements. Despite these capabilities, the poor radiative coupling to graphene plasmonic nanoresonators and low graphene carrier mobilities from imperfections in processed graphene samples have led to low light modulation depths in experimental attempts at creating tunable light modulation in graphene devices. In this talk, I will present multi-scale nanophotonic structure strategies to efficiently manipulate mid-infrared light using graphene plasmonic nanoresonators. Here, noble metal plasmonic structures are incorporated to significantly enhance lightmatter interactions in graphene as well as to bridge a large wavelength mismatch between free-space photons and graphene plasmons confined in deep-subwavelength-scale. The proposed strategy allowed experimental demonstration of electronically tunable perfect absorption in graphene, large modulation efficiencies in transmission, and complete complex amplitude modulation. In addition to the manipulation of mid-infrared light, I will discuss experimental observation of hot-plasmon-mediated mid-infrared light generation in graphene, which can be utilized for bright mid-infrared light sources.