Newport MKS Retroreflector, Solid Glass, N-BK7, 12.7 mm Diameter, 9.5 mm Height BGR-12.7

The BGR-12.7 Solid Glass Retroreflector is sometimes called a corner cube because the reflecting surfaces are three mutually perpendicular faces, like the corner of a cube. Light entering this 1/2 inch (12.7 mm) retroreflector with 9.5 mm height is reflected back 180°, and parallel to the original beam, regardless of its orientation to the beam. This makes retroreflectors valuable for applications requiring an exact 180° reflection without having to precisely orient the prism, reflected images are both inverted and reversed. The three reflective surfaces are uncoated, relying on total internal reflection (TIR), which gives them limitations at severe angles of incidence. They also must be kept clean for TIR to work properly.