and wherein the quarter wave plate is positioned such that {HEAD ~ the direction} of {TAIL ~ the slow axis} of the quarter wave plate and the S polarization direction are generally parallel 
and wherein the quarter wave plate is positioned such that { HEAD ~ the direction } of { TAIL ~ the slow axis } of the quarter wave plate and the S polarization direction are generally parallel
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH