Relative nonlinearity

Relative nonlinearity is a concept that often arises in the context of optics and materials science, particularly when discussing the nonlinear optical properties of materials. It refers to a comparison of the nonlinear response of a medium to the linear response, typically in the context of the refractive index or other properties. In nonlinear optics, materials can exhibit a nonlinear response to electromagnetic fields, meaning that their properties change in a nonlinear manner as the intensity of the light increases.