|MLA Citation:||Bloomfield, Louis A. "Question 1067"|
How Everything Works 21 Jan 2018. 21 Jan 2018 <http://howeverythingworks.org/print1.php?QNum=1067>.
Second, many light-emitting electronic devices emit infrared light. For example, the light emitting diodes in a television remote control unit emit infrared light. In this case, the infrared light is emitted by electrons that are shifting from one group of quantum levels in a semiconductor to another group—from conduction levels to valence levels. This emission isn't thermal radiation; it doesn't involve heat.
Lastly, some infrared light is produced by lasers. In this case, excited atoms or atomic-like systems amplify passing infrared light to produce enormous numbers of identical light particles—identical photons. Infrared industrial lasers are commonly used to machine everything from greeting cards to steel plates.