Retarder (Waveplate)

A class of materials that exhibit the characteristic of birefringence. Orthogonal components of light that enter a retarder (or waveplate) will experience a relative phase shift upon output. This phase shift is dependent upon the thickness of the retarding medium and the degree of birefringence. The axes of the material exhibit different index characteristics and are generally referred to as the fast (low index) and slow (high index) axes.