Abstract: An improved radiant energy distribution and detection apparatus for use with a device for detecting radiant energy reflected from a target zone includes an emission device for generation and emission of radiant energy, a device for redirecting radiant energy along a predetermined path and a detector device for sensing the presence of radiant energy reflected from the target zone. The emission device is stationary and emits a beam of radiant energy toward the redirecting device, which redirects the radiant energy along a primary beam path. The redirecting device also is configured for permitting a return beam of light from the target area to impinge upon the detector device, which is located therebehind with repect to the direction of travel of the return beam. A masking arrangement is employed for substantially limiting light reaching the detector to light from the return beam.