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