Near-Field Probe and Control of Excitons in 2D Materials with Plasmonic Nanostructures

We introduce a platform that leverages plasmonic metasurfaces to efficiently probe and control excitons in twodimensional materials. We employ a nonlocal pump-probe scheme, where surface plasmon polaritons (MPPs) induce a spatially modulated AC Stark shift in a monolayer of MoSe<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> located several microns away from the excitation spot. With tightly confined optical fields, we achieve a nearly two orders of magnitude reduction in the required modulation power compared to free-space optical illumination. Furthermore, we create a 1D optical lattice and observe exciton linewidth broadening as a robust signature of MPP-induced periodic sub-diffraction modulation. Our findings pave the way for power-efficient, lightinduced lattice phenomena below the diffraction limit in active, chip-compatible MPP architectures.