Mechanical scanning probe lithography of van der Waals antiferromagnetic CrSBr for fabrication of high-index waveguides and resonators

Recently emerged van der Waals antiferromagnetic CrSBr provides new opportunities for developing compact integrated photonic and optoelectronic devices since it exhibits high refractive index, strong excitonic response, and magnetic ordering. However, experimental methods for nanostructuring CrSBr to tailor its photonic properties are not yet well developed. Here we demonstrate photonic dispersion engineering in subwavelength-thick CrSBr slabs through patterning and creating slab photonic crystal structures. Using mechanical scanning probe lithography — a non-destructive technique benefiting from piezostage precision — we fabricate nanostructured CrSBr flakes of controlled geometry. Back-focal-plane reflectance spectroscopy measurements reveal modified photonic dispersion characteristics, with the photonic crystal dispersion tuned close to the CrSBr exciton resonance. The demonstrated engineering of the photonic dispersion in CrSBr, with tunable alignment between the photonic crystal resonance and the exciton energy, provides a base for further studies of exciton-photon interaction in 2D magnetic materials.