Broadband photo pumping of {HEAD ~ ions}, as from a flash lamp or {TAIL ~ other broadband source} of photons, to create a population inversion is highly inefficient because only a small fraction of the energy emanates within the very narrow range of wavelengths near the resonant absorption frequency of the transition 
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Broadband photo pumping of { HEAD ~ ions } , as from a flash lamp or { TAIL ~ other broadband source } of photons , to create a population inversion is highly inefficient because only a small fraction of the energy emanates within the very narrow range of wavelengths near the resonant absorption frequency of the transition
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH REL REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH