It’s often necessary to alter or manipulate the source’s polarization. For example, a reflective phase retarder converts linear to circular polarization and improves the laser cutting quality. (For reflective phase retarders, please see Phase Retarders.) However, most polarization altering devices -- the reflective phase retarder and waveplates -- are very wavelength sensitive and offer only narrowband, or single wavelength operation. The Fresnel prisms and rhombs described on this page utilize the principle that when light undergoes total internal reflection, there is a relative phase change between the s and p polarization components.
