Coupling between 2D Materials and Nanophotonic Cavities

Cavities are the ideal platform to investigate the light–matter interactions because they strongly confine and modulate the photons. Two‐dimensional (2D) materials such as transition metal dichalcogenides and hexagonal boron nitrite have unique electronic and optical properties, exhibiting excellent optical performance at the atomically thin nanoscale. The integration of 2D materials into cavities raises challenges in both the design and fabrication technologies. In this manuscript, the recent results of 2D‐material cavities are reviewed, in which the quality factor (Q‐factor) and smaller mode volume have been greatly improved. The nanostructure of cavities has been optimized to provide the homogeneous environment by encapsulating the 2D materials with hBN or polymer, which is crucial to improve the excitonic qualities and emission stability. These cavities are capable to integrate the 2D materials and their heterostructures, and enable the novel light–matter interaction phenomena such as the Bose–Einstein condensation of exciton‐photon polaritons. In addition, 2D materials are sensitive to the local environment such as the deformation arising from the strain or vibration, and thereby, enable the multi‐modal interaction with other physical degrees of freedom. These 2D‐material cavities indicate great potentials in the applications in quantum optical devices and quantum photonic technologies.