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Elliptical polarization. Linear polarization. the two orthogonal components are in phase. Circular polarization. the two orthogonal components have same amplitude and are +/-90 degrees out of phase. Elliptical polarization.
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Linear polarization • the two orthogonal components are in phase
Circular polarization • the two orthogonal components have same amplitude and are +/-90 degrees out of phase.
Elliptical polarization • the two components are not in phase and either do not have the same amplitude and/or are not 90 degrees out of phase
Wave plate • Optical device : a birefringent crystal with a chosen thickness • Light polarized along the extraordinary/fast axis propagates faster than the ordinary/slow axis. • Phase shift Δn : birefringence L : thickness of the crystal
Wave plate (cont.) • half-wave plate : retards 180 degrees, rotates the polarization direction of linear polarized light • quarter-wave plate : retards 90 degrees, changes linearly polarized light to circular.
Jones calculus • Polarized light is represented by a Jones vector, and linear optical elements are represented by Jones matrices.
Example: A half-wave plate: A quarter-wave plate: