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