Eigenpolarizations

Eigenpolarizations refer to specific states of polarization of light that remain unchanged in polarization as they propagate through an anisotropic medium. In such a medium, the speed of light depends on its polarization state. Eigenpolarizations are the unique polarization states for which the light travels at a single, constant speed within the medium. When light with an eigenpolarization state enters the anisotropic material, it exits with the same polarization state, although its phase may have changed.

These special polarization states arise due to the inherent symmetry of the material's optical properties. For a general anisotropic medium, there are typically two distinct eigenpolarizations. These are often orthogonal to each other. If the medium is birefringent, these two eigenpolarizations correspond to the ordinary and extraordinary rays, each traveling at a different speed. Understanding eigenpolarizations is crucial in fields like optics, photonics, and materials science, as they dictate how light interacts with and is transmitted through anisotropic materials. They are fundamental to explaining phenomena such as polarization rotation and the behavior of polarizing optical components.