stokes

Stokes parameters of polarized field

Syntax

Description

example

G = stokes(fv) returns the four Stokes parameters G of a polarized field or set of fields specified in fv. The field should be expressed in terms of linear polarization components. The expression of a field in terms of a two-row vector of linear polarization components is called the Jones vector formalism.

example

stokes(fv) displays the Stokes parameters corresponding to fv as points on the Poincare sphere.

Examples

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Stokes Vector

Create a left circularly-polarized field. Convert it to a linear representation and compute the Stokes vector.

cfv = [2;0];
fv = circpol2pol(cfv);
G=stokes(fv)
G =

    4.0000
         0
         0
    4.0000

Poincare Sphere

Display points on the Poincare sphere for a left circularly-polarized field and a 45 degree linear polarized field.

fv = [sqrt(2)/2, 1; sqrt(2)/2*1i, 1];
G = stokes(fv)
stokes(fv);
G =

    1.0000    2.0000
         0         0
         0    2.0000
    1.0000         0

The point at the north pole represents the left circularly-polarized field. The point on the equator represents the 45 degree linear polarized field.

Input Arguments

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fv — Field vector in linear polarization representation or linear polarization ratio1-by-N complex-value row vector or 2-by-N complex-value matrix

Field vector in its linear polarization representation specified as a 2-by-N complex-valued matrix or in its linear polarization ratio representation specified as a 1-by-N complex-valued row vector. If fv is a matrix, each column of fv represents a field in the form [Eh;Ev], where Eh and Ev are its horizontal and vertical linear polarization components. The expression of a field in terms of a two-row vector of linear polarization components is called the Jones vector formalism. If fv is a vector, each entry in fv is contains the polarization ratio, Ev/Eh.

Example: [sqrt(2)/2*1i; 1]

Data Types: double
Complex Number Support: Yes

Output Arguments

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G — Stokes parameters4-by-N matrix of Stokes parameters.

G contains the four Stokes parameters for each polarized field specified in fv. The Stokes parameters are computed from combinations of intensities of the field:

  • G0 describes the total intensity of the field.

  • G1 describes the preponderance of horizontal linear polarization intensity over vertical linear polarization intensity.

  • G2 describes the preponderance of +45° linear polarization intensity over -45° linear polarization intensity.

  • G3 describes the preponderance of right circular polarization intensity over left circular polarization intensity.

References

[1] Mott, H., Antennas for Radar and Communications, John Wiley & Sons, 1992.

[2] Jackson, J.D. , Classical Electrodynamics, 3rd Edition, John Wiley & Sons, 1998, pp. 299–302.

[3] Born, M. and E. Wolf, Principles of Optics, 7th Edition, Cambridge: Cambridge University Press, 1999, pp 25–32.

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