The beam then passes through {TAIL ~ mode matching means} 66 and finally through {HEAD ~ final amplifier stage} 82 
The beam then passes through { TAIL ~ mode matching means } 66 and finally through { HEAD ~ final amplifier stage } 82
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH