Nanostructured MoS2 monolayers for spatial control of second-harmonic generation

Monolayers of transition-metal dichalcogenides (TMDs) like Molybdenum Disulphide (MoS2) are direct-bandgap semiconductors with thicknesses below 1 nm. Due to their broken inversion symmetry, such monolayers feature a second-order nonlinear susceptibility, which is enhanced in spectral regions close to excitonic resonances [1].