Two-dimensional (2D) photonic materials have recently emerged as promising candidates for photonic and optoelectronic applications. Monoatomic-layer and few-layer materials can exhibit drastically different properties (optical, electrical, mechanical) compared to their bulk counterparts. The most famous example is graphene, but shortly after a broad range of novel sheet materials followed (black phosphorus, transition metal dichalcogenides (TMDs), MXenes, etc.), as well as heterostructures built from combinations of different monolayers. The objective here is to exploit the attractive properties of 2D materials, namely, their ample tunability upon electrical gating, their strong nonlinearity, and their ability for providing gain and emitting light. We have explored graphene for a broad range of nonlinear applications including third harmonic generation, optical bistability and all-optical switching based on saturable absorption. Our research activity in this area is recently focused on incorporating heterobilayers of transition metal dichalcogenides within photonic resonators in order to demonstrate pulsed and CW lasers.
