Editing Stokes parameters (section)

{{Short description|Set of values that describe the polarization state of electromagnetic radiation}}
[[File:Emmaalexander Stokes params.png|thumb|right|The Stokes I, Q, U and V parameters]]
The '''Stokes parameters''' are a set of values that describe the [[Polarization (waves)|polarization]] state of [[electromagnetic radiation]]. They were defined by [[George Gabriel Stokes]] in 1851,<ref>Stokes, G. G. (1851). On the composition and resolution of streams of polarized light from different sources. Transactions of the Cambridge Philosophical Society, 9, 399.</ref><ref>S. Chandrasekhar ''Radiative Transfer'', Dover Publications, New York, 1960, {{ISBN|0-486-60590-6}}, page 25</ref> as a mathematically convenient alternative to the more common description of [[coherence (physics)|incoherent]] or partially polarized radiation in terms of its total [[Intensity (physics)|intensity]] (''I''), (fractional) [[degree of polarization]] (''p''), and the shape parameters of the [[polarization ellipse]]. The effect of an optical system on the polarization of light can be determined by constructing the Stokes vector for the input light and applying [[Mueller calculus]], to obtain the Stokes vector of the light leaving the system. They can be determined from directly observable phenomena. The original Stokes paper was discovered independently by [[Francis Perrin (physicist)|Francis Perrin]] in 1942<ref>Perrin, F. (1942). Polarization of light scattered by isotropic opalescent media. The Journal of Chemical Physics, 10(7), 415-427.</ref> and by [[Subrahamanyan Chandrasekhar]] in 1947,<ref>{{cite web |url=https://www.aip.org/history-programs/niels-bohr-library/oral-histories/4551-2 |work=Oral History Interviews |title=S. Chandrasekhar - Session II |date=18 May 1977 |publisher=AIP}}</ref><ref>Chandrasekhar, S. (1947). The transfer of radiation in stellar atmospheres. Bulletin of the American Mathematical Society, 53(7), 641-711.</ref> who named it as the Stokes parameters.