Linearly polarized light entering a half-wave plate can be resolved into two waves, parallel and perpendicular to the optic axis of the waveplate. In the plate, the parallel wave propagates slightly slower than the perpendicular one. At the far side of the plate, the parallel wave is exactly half of a wavelength delayed relative to the perpendicular wave, and the resulting combination is a mirror-image of the entry polarization state (relative to the optic axis).
linearly polarized light entering a half-wave plate can be resolved into two waves parallel and perpendicular to the optic axis of the waveplate in the plate the parallel wave propagates slightly slower than the perpendicular one at the far side of the plate the parallel wave is exactly half of a wavelength delayed relative to the perpendicular wave and the resulting combination is a mirror-image of the entry polarization state (relative to the optic axis)