Mirror device for separating light beam emitted by a source and a coaxial reflected beam

摘要

In order to separate the beam F1 emitted by a source e.g. a laser 3 from the beam F2 reflected by a surface S following the same path there is used a mirror 1 which may be spherical having an aperture 2 which transmits the emitted beam and focuses the reflected beam on a photo-detector 6. Beam F1 may be scanned across the surface S using a scanning device e.g. mirrors 4 and 5.