In physics, specifically statistical mechanics, a population inversion occurs when a system (such as a group of atoms or molecules) exists in a state with more members in an excited state than in lower energy states. The concept is of fundamental importance in laser science because the production of a population inversion is a necessary step in the workings of a standard laser.
Read more about Population Inversion: Boltzmann Distributions and Thermal Equilibrium, The Interaction of Light With Matter, Selection Rules, Creating A Population Inversion, Other Methods of Creating A Population Inversion
Famous quotes containing the word population:
“It was a time of madness, the sort of mad-hysteria that always presages war. There seems to be nothing left but war—when any population in any sort of a nation gets violently angry, civilization falls down and religion forsakes its hold on the consciences of human kind in such times of public madness.”
—Rebecca Latimer Felton (1835–1930)