Riccardo Degl'Innocenti ; David S. Jessop ; Yash D. Shah ; Juraj Sibik ; Axel Zeitler ; Piran R. Kidambi ; Stephan Hoffman ; Harvey E. Beere ; David A. Ritchie
The integration of quantum cascade lasers with devices capable of efficiently manipulating terahertz light, represents a fundamental step for many different applications. Split-ring resonators, sub-wavelength metamaterial elements exhibiting broad resonances that are easily tuned lithographically, represent the ideal route to achieve such optical control of the incident light. We have realized a design based on the interplay between metallic split rings and the electronic properties of a graphene monolayer integrated into a single device. By acting on the doping level of graphene, an active modulation of the optical intensity was achieved in the frequency range between 2.2 THz and 3.1 THz, with a maximum modulation depth of 18%.