Beam splitter for producing a plurality of splitted light beams for each

Abstract

In a beam splitter for producing splitted light beams for each of first and second wavelength components of an incident light beam, first and second transparent blocks have first outgoing and second incident planar surfaces, respectively, which are bonded by an intermediate transparent layer with a band-pass layer and first and second subsidiary reflection layers interposed between the intermediate layer and the second incident planar surface and with the surfaces kept in parallel. Antireflection and primary reflection layers are formed on a first incident planar surface of the first transparent block that is parallel to the first outgoing surface. First and second semitransparent layers are formed on a second outgoing planar surface of the second transparent block that is parallel to the second incident planar surface. The incident light beam is directed from the antireflection layer towards the band-pass layer. The band-pass layer passes, towards the first semitransparent layer, a first outgoing light beam having the first wavelength component and reflects, towards the primary reflection layer, a second outgoing light beam having the second wavelength component to make the primary reflection layer reflect the second outgoing light beam towards the second semitransparent layer through the intermediate layer between the subsidiary reflection layers. In cooperation with the first and the second subsidiary reflection layers, the first and the second semitransparent layers produce the splitted light beams for the first and the second wavelength components, respectively.