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Lasing Medium
The active laser medium (also called gain medium or lasing medium) is the source of optical gain within a laser. The gain results from the stimulated emission of photons through electronic or molecular transitions to a lower energy state from a higher energy state previously populated by a pump source. Examples of active laser media include: * Certain crystals, typically doped with rare-earth ions (e.g. neodymium, ytterbium, or erbium) or transition metal ions (titanium or chromium); most often yttrium aluminium garnet ( Y3 Al5 O12), yttrium orthovanadate (YVO4), or sapphire (Al2O3); and not often Caesium cadmium bromide ( Cs Cd Br3) (Solid-state lasers) * Glasses, e.g. silicate or phosphate glasses, doped with laser-active ions; * Gases, e.g. mixtures of helium and neon (HeNe), nitrogen, argon, krypton, carbon monoxide, carbon dioxide, or metal vapors; (Gas lasers) * Semiconductors, e.g. gallium arsenide (GaAs), indium gallium arsenide (InGaAs), or gallium nitride (GaN). * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Rods 13
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light which is ''coherent''. Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances ( collimation), enabling applications such as laser pointers and lidar (light detection and ranging). Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum. Alternatively, temporal coherence can be used to produce ultrashort pulses of lig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
