Sub-wavelength optical lattice in 2D materials

TL;DR

This paper demonstrates a sub-wavelength optical lattice in 2D materials using metasurface plasmon polaritons, enabling highly efficient, spatially modulated light-matter interactions beyond the diffraction limit.

Contribution

It introduces a novel MPP-based scheme for creating sub-wavelength optical lattices in 2D materials, significantly reducing power requirements and enabling new light-induced phenomena.

Findings

Achieved nearly two orders of magnitude reduction in modulation power.

Demonstrated broadening of exciton linewidth as a signature of sub-diffraction modulation.

Enabled power-efficient, sub-wavelength light-matter interactions in 2D materials.

Abstract

Recently, light-matter interaction has been vastly expanded as a control tool for inducing and enhancing many emergent non-equilibrium 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 ``non-local" pump-probe scheme where MPPs are excited to induce a spatially modulated AC Stark shift for excitons in a monolayer of MoSe$_2$, several microns away from the illumination spot. Remarkably, 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.