A light beam output unit 212 combines {HEAD ~ two circularly polarized light beams} having {TAIL ~ opposite handedness} to each other to produce a composite light beam CB 
having
A light beam output unit 212 combines { HEAD ~ two circularly polarized light beams } having { TAIL ~ opposite handedness } to each other to produce a composite light beam CB
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH