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Related to population inversion: laser
population inversion[‚päp·yə′lā·shən in‚vər·zhən]
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.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
in physics, a state of a substance in which the higher energy levels of the constituent particles (such as atoms or molecules) are more “populated” by particles than are the lower levels. Under ordinary conditions (at thermal equilibrium) the inverse relation exists: there are fewer particles at the higher levels than at lower levels.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
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.
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