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:
“A multitude of little superfluous precautions engender here a population of deputies and sub-officials, each of whom acquits himself with an air of importance and a rigorous precision, which seemed to say, though everything is done with much silence, “Make way, I am one of the members of the grand machine of state.””
—Marquis De Custine (1790–1857)