nonlinear optics

Nonlinear optics is a field of science that studies how light interacts with matter when the light's intensity is very high. In these situations, the material's response is not simply proportional to the light's intensity, unlike in linear optics. This occurs when the electric field of the light wave is comparable to the electric fields within the atoms of the material, which is easily achieved with lasers.1

Nonlinear effects often result in the generation of light with frequencies different from the original light beam. A key example is frequency doubling, where light of one frequency passing through a nonlinear crystal produces light at twice that frequency. This field has important applications in areas like communications, photonics, and spectroscopy.12