As a result, the thickness of glass plate 203 must be precisely controlled so that there is {HEAD ~ minimal optical path length difference} between {TAIL ~ the two beam components} 233, 234 
As a result , the thickness of glass plate 203 must be precisely controlled so that there is { HEAD ~ minimal optical path length difference } between { TAIL ~ the two beam components } 233 , 234
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH