{HEAD ~ This laser beam d} causes {TAIL ~ the optical resonance action} to greatly change the emission level of the laser beam source 1 
causes
{ HEAD ~ This laser beam d } causes { TAIL ~ the optical resonance action } to greatly change the emission level of the laser beam source 1
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH