Hollow Retroreflector, Broadband, 63.5 mm, 5 arc sec, 225-700 nm

Retroreflectors, also known as corner cubes as all three mirror surfaces are perpendicular, will reflect all incoming light 180° regardless of incidence angle, resulting in a reflected beam that is precisely parallel to the incident beam. This is achieved without requiring prior alignment (as with a flat mirror). Images reflected by a corner cube are reversed and inverted.

Our broadband hollow retroreflectors are constructed of three front-surface flat mirrors assembled into a corner cube. A stress-free mounting technique is employed to ensure dimensional stability.

Hollow retroreflectors offer advantages of more accurate parallelism, ability to accommodate larger beam diameters, and better preservation of polarization compared to solid glass retroreflectors. Our UBBR1-1 hollow retroreflectors provide as low as 1 arc sec return beam accuracy, compared to 2 arc sec provided by our BGR solid glass retroreflectors. The UBBR2.5 hollow retroreflectors' 2.5-in. (63.5-mm) aperture is larger than typical solid glass retroreflectors' diameters. Polarized light traveling through solid glass can result in unpredictable polarization, whereas reflected light from a metallic coating traveling through air in a hollow retroreflector tends to have its polarization preserved better. Finally, for psec and fsec ultrashort pulses, hollow retroreflectors introduce much lower dispersive effects compared to solid glass.