For an observer looking against the beam, the rotation of course has the opposite direction. For example, left circular polarization means that the electric (and magnetic) field vector rotates in the left direction, seen in the direction of propagation. One distinguishes left and right circular polarization (see Figure 2). Effectively, this leads to a rapid rotation of the electric field vector – once per optical cycle – which maintains a constant magnitude. Circular and Elliptical Polarization Figure 2: Different polarization states of laser emission, illustrated for a few-cycle pulse propagating from left to right.Ī circular polarization state can mathematically be obtained as a superposition of electric field oscillations in the vertical and horizontal direction, both with equal strength but a relative phase change of 90°. Note that a rotation of the polarization by 180° does not lead to a physically distinct state. Of course, the polarization can have any other direction perpendicular to the beam axis. The electric field (red) oscillates in the vertical direction and the magnetic field (blue) in a direction perpendicular to the drawing plane. Figure 1: An electromagnetic wave traveling from left to right. In a different perspective, this is also shown in the second part of Figure 2. For example, a laser beam propagating in direction may have the electric field oscillations in the vertical () direction and the magnetic field oscillations in the horizontal () direction (see Figure 1) it can be called vertically polarized or -polarized. The direction of polarization is taken to be the direction of the electric field oscillations (i.e., not the magnetic ones). In the simplest case, a light beam is linearly polarized, which means that the electric field oscillates in a certain linear direction perpendicular to the beam axis, and the magnetic field oscillates in a direction which is perpendicular both to the propagation axis and the electric field direction. Linear Polarization The direction of polarization is associated with the electrical oscillations, not the magnetic ones. More specifically, light waves are recognized as electromagnetic transverse waves, i.e., with transverse oscillations of the electric and magnetic field. In many respects, light can be described as a wave phenomenon (→ wave optics). How to cite the article suggest additional literature Encyclopedia > letter P > Polarization of light Polarization Of Lightĭefinition: direction of the electric field oscillation of a light beamĬategories: general optics, laser devices and laser physics
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