Compact terahertz harmonic generation in the Reststrahlenband using a graphene-embedded metallic split ring resonator array

Abstract Harmonic generation is a result of a strong non-linear interaction between light and matter. It is a key technology for optics, as it allows the conversion of optical signals to higher frequencies. Owing to its intrinsically large and electrically tunable non-linear optical response, graphene has been used for high harmonic generation but, until now, only at frequencies