Another compensation mechanism is a birefringent displacer that has {TAIL ~ two sections} sandwiching a half wave plate, wherein the two sections are of different widths and {HEAD ~ the planar front surface} of the birefringent displacer can be positioned to be non orthogonal with respect to the incident input light beam 
Another compensation mechanism is a birefringent displacer that has { TAIL ~ two sections } sandwiching a half wave plate , wherein the two sections are of different widths and { HEAD ~ the planar front surface } of the birefringent displacer can be positioned to be non orthogonal with respect to the incident input light beam
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 OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH