Engineering THz-frequency light generation, detection, and manipulation through graphene

Graphene has been one of the most investigated materials in the last decade. Its unique optoelectronic properties have indeed raised it to an ideal and revolutionary candidate for the development of entirely novel technologies across the whole electromagnetic spectrum, from the microwaves to the x-rays, even crossing domain of intense application relevance, as terahertz (THz) frequencies. Owing to its exceptionally high tensile strength, electrical conductivity, transparency, ultra-fast carrier dynamics, nonlinear optical response to intense fields, electrical tunability, and ease of integration with semiconductor materials, graphene is a key disruptor for the engineering of generation, manipulation, and detection technologies with ad hoc properties, conceived from scratch. In this review, we elucidate the fundamental properties of graphene, with an emphasis on its transport, electronic, ultrafast and nonlinear interactions, and explore its enormous technological potential of integration with a diverse array of material platforms. We start with a concise introduction to graphene physics, followed by the most remarkable technological developments of graphene-based photodetectors, modulators, and sources in the 1–10 THz frequency range. As such, this review aims to serve as a valuable resource for a broad audience, ranging from novices to experts, who are keen to explore graphene physics for conceiving and realizing microscale and nanoscale devices and systems in the far infrared. This would allow addressing the present challenging application needs in quantum science, wireless communications, ultrafast science, plasmonics, and nanophotonics.