LOW-DISPERSION REFLECTOR

A retro-reflector comprising a front boundary surface configured for entry of measuring light into the retro-reflector and a back boundary surface configured for reflecting the measuring light as reflected measuring light. The front boundary surface and the back boundary surface are arranged on opposite sides of the retro-reflector, and an optical axis is defined by the arrangement of the front boundary surface and/or the back boundary surface of the retro-reflector, wherein an incidence angle of the measuring light relative to the optical axis is equal to an exit angle of the reflected measuring light relative to the optical axis. A first optical element is provided comprising the front boundary surface, and a second optical element is provided comprising the back boundary surface.