an unstable resonator positioned in a path along said third direction and disposed to transmit said beams therethrough, said beams comprising {HEAD ~ the output} of {TAIL ~ said unstable resonator} 
of
an unstable resonator positioned in a path along said third direction and disposed to transmit said beams therethrough , said beams comprising { HEAD ~ the output } of { TAIL ~ said unstable resonator }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL