population inversion (redirected from Inverse population)

population inversion

The 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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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.