Nanoantenna‐Sandwiched Graphene with Giant Spectral Tuning in the Visible‐to‐Near‐Infrared Region

Graphene exhibits intriguing electronic and optical properties, making it promising for integrating electronics and optics. Effective light modulation can be achieved by combining graphene with plasmonic metal structures. However, to tune plasmonic response with graphene at visible‐to‐near‐infrared frequencies has remained challenging owing to the weak coupling between plasmonic resonances and graphene optical transitions as well as inefficient gate control of the latter. Here the remarkable tuning of plasmonic scattering is reported by loading graphene into the cavities between Au nanocrystals and a Au film. The graphene‐loaded nanoantennas show dramatic resonance red shifts, which can further be modified by varying graphene dielectric screening effect. Such nanoantennas can therefore not only strengthen light−graphene interactions drastically but also exemplify an electroplasmonic system naturally. This study will open up an avenue for effectively operating graphene photonic devices in the visible‐to‐near‐infrared range and pave a way for electrically controlling light with plasmonic structures.