population inversion


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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.
References in periodicals archive ?
The nitrogen molecules from the air absorbed the electric energy and population inversion is created between the 3 upper level and B3 lower level.
b): Impulsive phase control of resonant gain and absorption represents a disruptive key technology rivalling the LASER especially in the hard-x-ray domain, where long-lived population inversion in dense media seems impossible.
The next way to generate the radiation is using p-Germanium laser which is based on population inversion between light and heavy holes.
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