Editing Stokes parameters (section)

===Stokes vectors===
The Stokes parameters are often combined into a vector, known as the '''Stokes vector''':
:<math>
\vec S \ =
\begin{pmatrix} S_0 \\ S_1 \\ S_2 \\ S_3\end{pmatrix}
=
\begin{pmatrix} I \\ Q \\ U \\ V\end{pmatrix}
</math>

The Stokes vector spans the [[vector space|space]] of unpolarized, partially polarized, and fully polarized light. For comparison, the [[Jones vector]] only spans the space of fully polarized light, but is more useful for problems involving [[coherence (physics)|coherent]] light. The four Stokes parameters are not a preferred [[coordinate system]] of the space, but rather were chosen because they can be easily measured or calculated.

Note that there is an ambiguous sign for the <math>V</math> component depending on the physical convention used. In practice, there are two separate conventions used, either defining the Stokes parameters when looking down the beam towards the source (opposite the direction of light propagation) or looking down the beam away from the source (coincident with the direction of light propagation). These two conventions result in different signs for <math>V</math>, and a convention must be chosen and adhered to.

====Examples====
Below are shown some Stokes vectors for common states of polarization of light.

:{|
 |-
 | <math>\begin{pmatrix} 1 \\ 1 \\ 0 \\ 0\end{pmatrix}</math> || Linearly polarized (horizontal)
 |-
 | <math>\begin{pmatrix} 1 \\ -1 \\ 0 \\ 0\end{pmatrix}</math> || Linearly polarized (vertical)
 |-
 | <math>\begin{pmatrix} 1 \\ 0 \\ 1 \\ 0\end{pmatrix} </math> || Linearly polarized (+45°)
 |-
 | <math>\begin{pmatrix} 1 \\ 0 \\ -1 \\ 0\end{pmatrix}</math> || Linearly polarized (−45°)
 |-
 | <math>\begin{pmatrix} 1 \\ 0 \\ 0 \\ 1\end{pmatrix} </math> || Right-hand circularly polarized
 |-
 | <math>\begin{pmatrix} 1 \\ 0 \\ 0 \\ -1\end{pmatrix}</math> || Left-hand circularly polarized
 |-
 | <math>\begin{pmatrix} 1 \\ 0 \\ 0 \\ 0\end{pmatrix}</math> || Unpolarized
|}