Planar Optical Cavities Hybridized with Low‐Dimensional Light‐Emitting Materials

Abstract Low‐dimensional light‐emitting materials have been actively investigated due to their unprecedented optical and optoelectronic properties that are not observed in their bulk forms. However, the emission from low‐dimensional light‐emitting materials is generally weak and difficult to use in nanophotonic devices without being amplified and engineered by optical cavities. Along with studies on various planar optical cavities over the last decade, the physics of cavity–emitter interactions as well as various integration methods are investigated deeply. These integrations not only enhance the light–matter interaction of the emitters, but also provide opportunities for realizing nanophotonic devices based on the new physics allowed by low‐dimensional emitters. In this review, the fundamentals, strengths and weaknesses of various planar optical resonators are first provided. Then, commonly used low‐dimensional light‐emitting materials such as 0D emitters (quantum dots and upconversion nanoparticles) and 2D emitters (transition‐metal dichalcogenide and hexagonal boron nitride) are discussed. The integration of these emitters and cavities and the expect interplay between them are explained in the following chapters. Finally, a comprehensive discussion and outlook of nanoscale cavity‐emitter integrated systems is provided.