Tunable optical non-linearity in mono-layer semiconductors

Excitons in monolayer TMDC semiconductors provide a unique platform for achieving strongly non-linear light-matter interactions. Starting from the linear response of 2D excitons, several approaches have successfully demonstrated enhanced non-linearities as the phase space available to excitons is reduced. Such approaches include local strain engineering, moiré potentials, and trion saturation. Recent studies have further demonstrated the ability to quantum confine neutral excitons in 2D TMDCs using electrostatic gating [1], allowing for the deterministic positioning of tunable quantum emitters.

Here we leverage this new technique to control the optical non-linearity of 2D TMDCs excitons across different regimes of confinement. This approach is a promising starting point for scalable devices with strong photon-photon interactions. In turn, such interacting states of photons could provide a route to realize quantum many-body phases of light, with potential applications in quantum light technologies and optical computing.

[1] Thureja, D., et al. Electrically tunable quantum confinement of neutral excitons. Nature 606, 298–304 (2022).