The quarter wave plate 828 converts the the components of the composite light beam to clockwise circularly polarized light and {HEAD ~ counterclockwise circularly polarized light}, and the beam expander 829 expands {TAIL ~ the composite light beam CB4} to have a relatively large diameter 
The quarter wave plate 828 converts the the components of the composite light beam to clockwise circularly polarized light and { HEAD ~ counterclockwise circularly polarized light } , and the beam expander 829 expands { TAIL ~ the composite light beam CB4 } to have a relatively large diameter
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH