Beam splitter for changing optical paths small tilt

摘要

In the disclosed beam splitter, a first prism has an entrance face, an inclined face, and a mirrored face for totally reflecting a beam reflected from the inclined face back to the inclined face. A second prism has an entrance face in parallel with the inclined face of the first prism, and two exit faces. One of the exit faces of the second prism cooperates with the mirrored face of the first prism. When the first and second prisms are turned as a unit, the inclined face of the first prism either passes a light beam arriving from the entrance face through to the second prism and out one of the exit faces or totally reflects the arriving light beam to the mirrored face. The light beam reflected back from the mirrored face now passes through the inclined face to the second prism and out the cooperating exit face of the second prism.