Dielectric structures can support low-absorption optical modes, which are attractive for engineering light-matter interactions with excitonic resonances in two-dimensional (2D) materials. However, the coupling strength is often limited by the electromagnetic field being confined inside the dielectric, reducing spatial overlap with the active excitonic material. Here, we demonstrate a scheme for enhanced light-matter coupling by embedding excitonic tungsten disulfide (WS2) within dielectric hexagonal boron nitride (hBN), forming a van der Waals (vdW) heterostructure that optimizes the field overlap and alignment between excitons and optical waveguide modes. To tailor diffractive coupling between free-space light and the waveguide modes in the vdW heterostructure, we fabricate Fourier surfaces in the top hBN layer using thermal scanning-probe lithography and etching, producing sinusoidal topographic landscapes with nanometer precision. We observe the formation of exciton-polaritons with a Rabi splitting indicating that the system is at the onset of strong coupling. These results demonstrate the potential of Fourier-tailored vdW heterostructures for exploring advanced optoelectronic and quantum devices.
@article{arxiv.2502.02114,
title = {Fourier-Tailored Light-Matter Coupling in van der Waals Heterostructures},
author = {Dorte R. Danielsen and Nolan Lassaline and Sander J. Linde and Magnus V. Nielsen and Xavier Zambrana-Puyalto and Avishek Sarbajna and Duc Hieu Nguyen and Timothy J. Booth and Nicolas Stenger and Søren Raza},
journal= {arXiv preprint arXiv:2502.02114},
year = {2025}
}