population inversion
noun Physics.
a condition of matter in which more electrons are in a high energy state than in a lower energy state, as is required for the operation of a laser.
Origin of population inversion
First recorded in 1960–65
Words nearby population inversion
populate,
population,
population control,
population explosion,
population genetics,
population inversion,
population parameter,
population pressure,
population pyramid,
populism,
populist
Scientific definitions for population inversion
population inversion
The condition of having enough excited or high-energy states distributed throughout a substance to sustain a chain-reaction of stimulated emission. Lasers, for example, need a constant power source that maintains population inversion in order to generate radiation continuously, since each stimulated emission reduces the population of high-energy states. See also stimulated emission.