Cat’s eye retroreflector,

A drawing of this visible/UV interferometer appears in Figure 6. One important design variation which differs from Figure 1 is the fact that the interferometer mirrors used to reflect the radiation back to the beam splitter are now cat s-eye retroreflectors. These... 

T. Takatsuji, M. Goto, S. Osawa, R. Yin, T. Kurosawa, Whole-viewing-angle cat s-eye retroreflector as a target of laser trackers. Meas. Sci. Technol. 10 (1999) pp. 87-90. 

An alternative interferometer to the cube-corner is the cat s-eye interferometer, where the cube-corners are replaced by cat s-eye retroreflectors. These are components that consist of one parabolic and one spherical mirror, and reflect an incident ray back in the opposite direction. Cat s-eye interferometers are also used in high-resolution spectroscopy. 

Beer, R. Marjaniemi, D. (1966). Wavefronts and consbuction tolerances for the cat s-eye retroreflector. Applied Optics, 5,1191-7. 

In certain types of mirror surfaces the reflected beam is returned in the same direction from which the incident beam arrived. This is maintained over a wide range of directions of the incident beam (Fig. 2.40). The phenomenon is called retroreflection [258]. Retroreflectors are various kinds of catadioptric stractures ( cat s eyes ). Basically, a retroreflector may be a surface-diffractive structure with triangular, pyramidal, spherical, etc. shapes of the grating. Incident light typically reflects twice before returning in the direction it came from. 

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