A phase-compensating cube corner retroreflector includes three rear
reflecting surfaces. The first and the third rear reflecting surfaces can
be coated with a phase-compensating film stack that induces 2n.pi. phase
difference upon reflection, where n is an integer including 0.
Alternatively, all three rear reflecting surfaces can be coated with a
phase-compensating film stack that induces n.pi. phase difference when
handling linearly polarized light, or 2n.pi. phase difference when
handling linearly or circularly polarized light. So coated, the
phase-compensating cube corner preserves the polarization orientation and
ellipticity of the incident light. Such a phase-compensating cube corner
can be used to improve the accuracy of distance-measuring
interferometers. The cube corner directs light to and from other optical
elements, including a polarizing beam-splitters, mirrors, and
quarter-wave plates.