Nd-YAG laser
Acronym for Neodymium-doped Yttrium Aluminum Garnet, a compound that is used as the lasing medium for certain solid-state lasers. Nd:YAG lasers emit light with a wavelength of 1064 nm, in the infrared. Usually, Nd:YAG lasers are pulsed lasers, that is, they emit short high-intensity pulses as opposed to a continuous beam. Typically, the pulses have a repetition frequency of 5 to 50 hertz, with an energy of up to several joules per pulse and a duration on the order of nanoseconds.
YAG is a host material for the neodymium atoms that are chiefly responsible for the lasing action. Other common host materials for neodymium are: YLF (yttrium lithium fluoride, 1054 nm), YVO (yttrium vanadate, 1054 nm), and glass. A particular host material is chosen in order to obtain a desired combination of optical, mechanical, and thermal properties. Nd:YAG lasers and variants are pumped either by flash lamps, continuous gas-discharge lamps, or near-infrared laser diodes.
For many applications, the infrared light is frequency-doubled or -tripled in order to obtain visible (527 or 532 nm, green) or ultraviolet light.
Recently, affordable laser pointers emitting a green beam based on a frequency doubled Nd-YAG laser have become available. Much brighter than the common red laser pointers, the beam can be seen in midair.
