In optical systems often it is necessary to isolate a single state of polarization of light. Many interferometric and spectroscopic systems are sensitive to polarization. Polarization can even play a role in laser-based cutting, for example, in which the shape of the cutting region becomes highly anisotropic when polarized light is used. Linear and even circular polarization can be obtained using a “polarizer,” or a component that transmits a single state of polarization while absorbing, reflecting, or deviating light with the orthogonal state of polarization. Optical applications that depend on good polarization control include laser materials processing, polarization diversity detection in communications and rangefinding, liquid crystal device characterization and manufacturing, fluorescence polarization assays and imaging, second-harmonic generation imaging, polarized Raman spectroscopy, and a wide variety of laboratory laser applications based on holography, interferometry, etc., to name a few.