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population inversion |
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population inversionThe condition that occurs when a material is radiated with another material at a certain wavelength, causing electrons to jump to a higher orbit (higher shell). When the electrons return to their ground state, they spontaneously emit a photon. Population inversion is the reason a laser works. The spontaneous emission of photons is amplified by mirrors causing a chain reaction and further stimulation of the excited atoms to release photons. See laser. population inversion [‚päp·yə′lā·shən in‚vər·zhən] (atomic physics) The condition in which a higher energy state in an atomic system is more heavily populated with electrons than a lower energy state of the same system. How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content. |
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| The result is a population inversion in which there are more particles in the higher-energy state than in the ground state. Javan et al developed the cold helium-neon laser, basing its mechanism on the transfer of excitation from helium to neon atoms by population inversion and continuous optical maser oscillation. To achieve the population inversion, scientists must "pump" the material with energy from an outside source in such a way that it will invest the energy, or part of it, in the level from which the lasing transition takes place. |
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