The generator comprises an envelope and two mirrors defining {TAIL ~ a resonant cavity}, in which is maintained {HEAD ~ a monolithic wave guide} with a capillary 
in is maintained
The generator comprises an envelope and two mirrors defining { TAIL ~ a resonant cavity } , in which is maintained { HEAD ~ a monolithic wave guide } with a capillary
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH REL OTH REL REL HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH