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.

Nearby words

  1. populate,
  2. population,
  3. population control,
  4. population explosion,
  5. population genetics,
  6. population parameter,
  7. population pressure,
  8. population pyramid,
  9. populism,
  10. populist

Origin of population inversion

First recorded in 1960–65

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Science 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.
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