subject: LASERS AND THEIR WORKING MECHANISMS [print this page] Principle of operation of lasers: Consider a group of atoms all in the same excited state. A passing photon may cause stimulated emission in one of these atoms. This results in the emission of two photons. Each of these photons may cause induced emission in two other excited atoms. This process may continue in a chain reaction. The result will be an intense beam of photons moving in the same direction and all are coherent.
