The system 7, wherein {HEAD ~ the first and second diffractive structures} are on {TAIL ~ a same surface} 
are on
The system 7 , wherein { HEAD ~ the first and second diffractive structures } are on { TAIL ~ a same surface }
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL