Broadband photo pumping of ions, as from a flash lamp or 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 {HEAD ~ wavelengths} near {TAIL ~ the resonant absorption frequency} of the transition 
Broadband photo pumping of ions , as from a flash lamp or 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 { HEAD ~ wavelengths } near { TAIL ~ the resonant absorption frequency } of the transition
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 OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH