Van der Waals waveguide quantum electrodynamics probed by infrared nano- photoluminescence

Atomically layered van der Waals (vdW) materials exhibit remarkable properties, including highly-confined infrared waveguide modes and the capacity for infrared emission in the monolayer limit. Here, we engineered structures that leverage both of these nano-optical functionalities. Specifically, we encased a photoluminescing atomic sheet of MoTe2 within two bulk crystals of WSe2, forming a vdW waveguide for the embedded light-emitting monolayer. We discovered spatially-structured emission from MoTe2 that utilizes waveguide modes of WSe2 slabs. This nano-structured emission was captured with spectrally-resolved nanoscale photoluminescence microscopy (nano-PL). Our quantum electrodynamical (QED) model synthesizes nano-PL observables with far-field emission lifetimes, quantifying the intensity radiated into each mode of the waveguide. Our work marks a significant advance in the implementation of all-vdW waveguide-QED devices.