Silicon nanospheres boost WS₂ second-harmonic generation 40-fold while preserving polarization

A research team has demonstrated that silicon nanospheres can strongly enhance second-harmonic generation (SHG) from an atomically thin semiconductor while preserving the circular polarization information tied to its valley degree of freedom. The study, published in Nano Letters, provides design guidelines for efficient, polarization-preserving nonlinear light sources at the nanoscale.