How Lasers Work
A laser is a device that release light over a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term “laser” comes as an acronym for “light amplification by stimulated emission of radiation”.
A laser is produced when the electrons in atoms in special glasses, crystals, or gases absorb energy from an electrical current or another laser and become “excited.” Than the excited electrons goes from a lower-energy orbit to a higher-energy orbit around the atom’s nucleus. When the electrons return to their normal state, they emit photons (particles of light).
All photons are at the same wavelength and are “coherent,” that means the crests and troughs of the light waves are all in lockstep. In contrast, ordinary visible light consists of multiple wavelengths and is not coherent.
The stimulated emission of light was a discovery by Albert Einstein around 1916.
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