Light modulation based on the enhanced Kerr effect in molybdenum disulfide nanostructures with curved features

A novel type of molybdenum disulfide (MoS₂) nanoparticles (NPs) was chemically synthesized, which possessed curved features with three-dimensional (3D) freedom compared with planar two-dimensional (2D) materials. Due to the introduction of curved features, the synthesized NPs exhibited a strongly enhanced nonlinear refractive index (n₂ ∼ 10^-5 cm^-2 W^-1) and third-order susceptibility (χ⁽³⁾ ∼ 10^-7 esu), which were experimentally verified by the spatial self-phase modulation effect in the visible wavelength range. Both the nonlinear parameters were two orders of magnitude higher than their planar MoS₂ nanostructure counterparts. In addition, the relative change of the effective nonlinear refractive index Δn₂/n₂ was found to be distinctly dependent on the intensity of the applied electromagnetic field. Moreover, an all-optical modulation was experimentally realized based on the spatial cross-phase modulation effect. Our results demonstrate planar MoS₂ materials with 3D features as potential candidates for next generation all-optical applications and open a substantial approach for the design of efficient nanomaterials with favorable optical nonlinearity.