The thickness of multistage wave plate is equal to multiple full-wave thicknesses plus one required delay thickness. Multistage plates are relatively easy to manufacture, but they are sensitive to temperature, wavelength, and incident Angle.
Wave plate, also known as phase delay plate, is an optical element that changes the polarization state of light by producing optical path difference (or phase difference) between two mutually orthogonal polarization components. The outgoing light is different when the incident light passes through the wave plate with different types of parameters, which can be wired polarized light, elliptic polarized light, circular polarized light, etc. The main materials of wave plate are quartz, mica, calcite and other birefringent crystals.