Embedding Air-Sensitive Magnetic Heterostructures Inside an Optical Micro-Cavity for Magnetically Tunable Polaritons

The assembly of two-dimensional heterostructures using van der Waals (vdW) materials has created opportunities to harness layer-specific properties in engineered devices. A prime example is layer-dependent magnetism, as observed in CrI₃, paving the way for devices with tailored layer-dependent magnetic properties. For example, combining CrI₃ with transition metal dichalcogenide (TMD) monolayers results in interfacial charge transfer that bestows magnetic characteristics upon the TMD trion emission. Past demonstrations of exciton-polaritons in vdW materials embedded in micro-cavities have indicated regimes where polariton optical response can be magnetically modulated. Although magnetic responses of polaritons in layered bulk 2D magnetic materials have been reported, the unique features of magnetic heterostructures remain relatively unexplored. A significant challenge is the air sensitivity of many magnetic vdW materials, which has supported an emphasis on bulk attributes over layer-dependent or monolayer effects in polaritons. Here, we report on the fabrication of magnetic layered heterostructures designed for cavity polaritons. A strategy is presented to address assembly challenges with embedding air-sensitive CrI₃/WSe₂ heterostructures within an optical micro-cavity.