Nonlinear nanophotonics with 2D transition metal dichalcogenides

Two-dimensional (2D) transition metal dichalcogenides (TMDs) possess many extraordinary electronic, mechanical, optical and chemical properties, which have brought new possibilities for the exploration of 2D physics and a wide range of applications. Recently, the nonlinear optical properties of atomically thin 2D TMDs have attracted lots of attention. The asymmetric structure and ease of integration make 2D TMDs especially suitable for many novel nonlinear nanophotonic applications. Here, we review the recent progress in the field of nonlinear nanophotonics based on 2D TMDs. A general introduction to 2D TMDs, in particular, to their distinctive photonic properties, is given. We then discuss the recent investigation of the nonlinear properties of 2D TMDs including harmonic generation and saturable absorption, followed by various approaches for enhancing the nonlinear response of 2D TMDs. Several examples of the potential for nonlinear nanophotonics based on 2D TMDs are also presented.