Zero-Order Waveplate, Half-Wave, Quartz, 25.4 mm Diameter, 1300 nm

A half-wave plate can rotate the plane of polarization from a polarized laser to any other desired plane. Suppose a plane-polarized wave is normally incident on a wave plate, and the plane of polarization is at an angle θ with respect to the fast axis. To see what happens, resolve the incident field into components polarized along the fast and slow axes, as shown. After passing through the plate, pick a point in the wave where the fast component passes through a maximum. Since the slow component is retarded by one half-wave, it will also be a maximum, but 180° out of phase, or pointing along the negative slow axis. If we follow the wave further, we see that the slow component remains exactly 180° out of phase with the original slow component, relative to the fast component. This describes a plane-polarized wave, but making an angle θ on the opposite side of the fast axis. Our original plane wave has been rotated through an angle 2θ.

Quartz waveplates are more sensitive to incidence angle than our Polymer waveplates. Polymer waveplates have excellent angular field of view and the retardation changes by less than 1% over a ±12° incidence angle.