Lasers

Abstract

AbstractLaser is an acronym for Light Amplification by Stimulated Emission of Radiation that describes the basic physical principle of its operation. Gordon, Zeiger and Townes [8.1] showed for the first time in 1955 that a microwave could be amplified by NH3 molecules on the inversion transition at λ = 1.26 cm (Fig.4.13) if these molecules were prepared in such a way that the upper level of the transition had a larger population than the lower one. With such inverted NH3 molecules inside a microwave cavity, the first “maser” (microwave amplification by stimulated emission of radiation) could be operated.KeywordsPump PowerActive MediumResonator ModeLaser EmissionLaser OscillationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.