Hyper–Rayleigh scattering

Hyper-Rayleigh scattering (HRS) is a nonlinear optical phenomenon that involves the scattering of light by molecules. Specifically, it refers to the scattering of light from a medium that exhibits a second-order nonlinear optical response. When a light wave interacts with a material, it can generate new frequencies through the nonlinear interaction of the electromagnetic field with the electronic structure of the molecules in that material.