Stokes parameters

Stokes parameters are a set of four values that fully describe the polarization state of electromagnetic radiation, particularly light.

Named after physicist George Stokes, they quantify total intensity plus three aspects of polarization: horizontal/vertical preference, diagonal preference, and circular polarization.

Unlike other descriptions of polarization, Stokes parameters can represent partially polarized and unpolarized light, making them practical for real-world optics and astronomy: The Stokes parameters revealed the starlight was twenty percent polarized.