Reshaping the emission of a THz quantum cascade laser frequency comb through an on-chip graphene modulator

Graphene possesses a peculiar potential for the development of optoelectronic components capable to actively manipulate infrared light [1] . Its electrostatically tunable optical conductivity, band structure and transport characteristics, and the possibility to be grown over large areas, offer an intriguing playground for engineering, at the nanoscale, amplitude modulators, spatial light modulators and switches, combining high efficiency (> 50%) intensity modulation, reasonably high speeds (> s response times), and spectral tunability in the underexploited high (> 1.5 THz) terahertz-frequency range [2] , where frontier applications in quantum communications, quantum computing, adaptive and quantum optics are still at their infancy.