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