Superior third-order nonlinearity in inorganic fullerene-like WS_(2) nanoparticles

Two-dimensional(2D)transition metal dichalcogenides(TMDs)attain increasing attention due to their exceptional nonlinear optical efficiencies,which hold promising potential for on-chip photonics and advanced optoelectronic applications.Planar TMDs have been proven to support orders-higher third-order nonlinear coefficients in comparison with common nonlinear materials.Interestingly,stronger light–matter interaction could be motivated when curved features are introduced to 2D TMDs.Here,a type of inorganic fullerene-like WS_(2) nanoparticles is chemically synthesized using hard mesoporous silica.By using the spatial self-phase modulation(SSPM)method,the nonlinear refractive index n_(2) and third-order susceptibility χ^((3))are investigated in the visible range.It is found that n_(2)∼10^(−5) cm^(2)∕W andχ^((3))∼10^(−7) esu,two orders higher than the counterparts of planar WS_(2) structures.Our experimental findings provide a fresh thinking in designing nonlinear optical materials and endow TMDs with new potentials in photonic integration applications.