Linear polarization

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Diagram of the electric field of a light wave (blue), linear-polarized along a plane (purple line), and consisting of two orthogonal, in-phase components (red and green waves)

In electrodynamics, linear polarization or plane polarization of electromagnetic radiation is a confinement of the electric field vector or magnetic field vector to a given plane along the direction of propagation. See polarization for more information.

The orientation of a linearly polarized electromagnetic wave is defined by the direction of the electric field vector.[1] For example, if the electric field vector is vertical (alternately up and down as the wave travels) the radiation is said to be vertically polarized.

Mathematical description of linear polarization[edit]

The classical sinusoidal plane wave solution of the electromagnetic wave equation for the electric and magnetic fields is (cgs units)

for the magnetic field, where k is the wavenumber,

is the angular frequency of the wave, and is the speed of light.

Here is the amplitude of the field and

is the Jones vector in the x-y plane.

The wave is linearly polarized when the phase angles are equal,

.

This represents a wave polarized at an angle with respect to the x axis. In that case, the Jones vector can be written

.

The state vectors for linear polarization in x or y are special cases of this state vector.

If unit vectors are defined such that

and

then the polarization state can be written in the "x-y basis" as

.

See also[edit]

References[edit]

  • Jackson, John D. (1998). Classical Electrodynamics (3rd ed.). Wiley. ISBN 0-471-30932-X. 
  1. ^ Shapira, Joseph; Shmuel Y. Miller (2007). CDMA radio with repeaters. Springer. p. 73. ISBN 0-387-26329-2. 

External links[edit]

 This article incorporates public domain material from the General Services Administration document "Federal Standard 1037C".