nonlinear optical effects

Nonlinear optical effects occur when intense light interacts with a material, causing the material's response to change depending on the light's strength. Unlike standard light interactions, where the material's reaction is proportional to the light's intensity, nonlinear effects involve complex behaviors such as generating new colors (frequencies), changing light directions, or altering its speed. These phenomena are essential for technologies like laser editing, telecommunications, and medical imaging. They happen because, at high light intensities, the atoms in the material behave in ways that produce unexpected and useful changes in the light itself.