Precision Glass & Optics (PG&O) (Santa Ana, CA) has announced a line of Littrow dispersion prisms for laser cavities and other optical systems, such as spectrographs. PG&O offers a wide range of coated and uncoated Littrow prisms featuring 30- 60- and 90-degree angles. Uncoated prisms are ideal for image (or light) dispersion because they can disperse white light into its spectral components. Coated Littrow prisms feature an anti-reflective coating on the surface opposite the 60-degree angle to provide a constant deviation prism. For a given wavelength, the refracted ray entering the prism travels normally to the reflectively-coated exit face, then back along its original path. Littrow prisms from PG&O feature angular tolerance >1 arc second, surface quality of 10/5, surface accuracy λ/20, and dimensional tolerances ± .001 in.