Electrically driven heterostructured far-infrared wire lasers with integrated graphene plasmons

Photonic technologies that exploit surface plasmons in graphene can offer groundbreaking opportunities for the development of compact and inexpensive active photonic devices, owing to the unique combination of tight field localization, giant optical nonlinearities and electrostatic gating tuning. Here we take advantage of this unique combination of properties to engineer frequency up-converted, electrically driven, single-mode photonic sources in the 9.0–10.5 THz range, with an emission frequency entirely tunable by design. We excite plasmons confined in a multilayer graphene micro-ribbon grating within a distributed-feedback terahertz quantum cascade laser that incorporates a top supercapacitor to tune the graphene Fermi energy, demonstrating third harmonic generation. Our monolithic, electrically driven laser works in the inaccessible Reststrahlen band of its core III–V semiconductor heterostructure and shows a peak power of ~9 μW, laying the foundation of a new generation of plasmonic, nonlinear light-emitting sources.