Germanium right angle prisms are used in optical systems for beam steering and folding applications. They are made of germanium (Ge) and deflect light by 90 degrees through two reflections, thereby causing the image to deflect and stand upright. Germanium is a popular material for use in IR optical systems because it has a high index of refraction and transmits over a broad spectral range from 2 to 14 microns. Based on the principle of total internal reflection (TIR), right-angle prisms can be used as 90-degree reflection mirrors or 180-degree retroreflectors. In addition to the losses caused by reflection, total internal reflection can exhibit a 100% reflectivity over a wide range of wavelengths.