population inversion


Also found in: Thesaurus, Medical, Encyclopedia, Wikipedia.
Related to population inversion: laser

population inversion

n.
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, require population inversion in order to generate radiation.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
References in periodicals archive ?
A critical step in the lasing is the injection of a large amount of electrical current into the organic layers to achieve a condition called population inversion. However, the high resistance to electricity of many organic materials makes it difficult to get enough electrical charges in the materials before they heat up and burn out.
The nitrogen molecules from the air absorbed the electric energy and population inversion is created between the 3 upper level and B3 lower level.
It is well known fact that working principle of doped fiber amplifier (TDFA under consideration) is population inversion. The gain of TDFA depends on the metastable state ions.
Full browser ?