Graphene metasurfaces engineered with organic molecules

Layered graphene metasurfaces functionalized with graded pattern of organic molecules will be investigated to manipulate optical beams with great flexibility. The optical property of graphene is modified by molecules through charge transfer and band shape modification. By patterning one or two types of organic molecules on the graphene surface (digital metasurface), desired plasmonic response will be tailored leading to novel applications for surface wave engineering or reflection/transmission/absorption manipulation. The former is enabled due to the gradient effective index profile for surface wave by weighting two types of molecules. The latter is realized through resonance control of the unit cell, where the metasurface is acting as an atom-thick impedance sheet with values locally tunable by the configuration of molecular patterns.