Journal ArticleSub-wavelength optical lattice in 2D materialsSarkar, Supratik; Mehrabad, Mahmoud Jalali; Suárez-Forero, Daniel G; Gu, Liuxin; Flower, Christopher J; Xu, Lida; Watanabe, Kenji; Taniguchi, Takashi; Park, Suji; Jang, Houk; Zhou, You; Hafezi, MohammadRecently, light-matter interaction has been vastly expanded as a control tool for inducing and enhancing many emergent nonequilibrium phenomena. However, conventional schemes for exploring such light-induced phenomena rely on uniform and diffraction-limited free-space optics, which limits the spatial resolution and the efficiency of light-matter interaction. Here, we overcome these challenges using metasurface plasmon polaritons (MPPs) to form a sub-wavelength optical lattice. Specifically, we report a “nonlocal” pump-probe scheme where MPPs are excited to induce a spatially modulated AC Stark shift for excitons in a monolayer of MoSe₂, several microns away from the illumination spot. We identify nearly two orders of magnitude reduction for the required modulation power compared to the free-space optical illumination counterpart. Moreover, we demonstrate a broadening of the excitons’ linewidth as a robust signature of MPP-induced periodic sub-diffraction modulation. Our results will allow exploring power-efficient light-induced lattice phenomena below the diffraction limit in active chip-compatible MPP architectures.Science2025-03-2810635041Science Advances11132375-2548https://doi.org/10.1126/sciadv.adv20232145712National Science Foundation