Population inversion | 農藥百科
![Population inversion](https://i.imgur.com/WMTbIbA.jpg)
Populationinversionisastateofamediumwhereahigher-lyingelectroniclevelhasahigherpopulationthanalower-lyinglevel.
![Population inversion](https://i.imgur.com/WMTbIbA.jpg)
Definition[1]: a state of a medium where a higher-lying electronic level has a higher population than a lower-lying level
German: Besetzungsinversion[2]
Category: physical foundations[3][4]
How to cite the article; suggest additional literature[5][6]
Author: Dr. Rüdiger Paschotta[7]
URL: https://www.rp-photonics.com/population_inversion.html[8]
Population inversion is a state of a system, for example a laser gain medium[9], where a higher-lying energy level is more strongly populated than a lower-lying level. This cannot occur under conditions of thermal equilibrium, where the level populations are described by a Boltzmann distribution. However, a population inversion is often easily achieved by optical pumping[10] at a suitable optical wavelength[11]...