Laser

A LASER (Light Amplification by Stimulated Emission of Radiation) is an optical source composed of a resonant optical cavity and a gain medium.

Common laser types

For a more complete list of laser types see list of laser types.

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Color

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Wavelength interval

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Frequency interval

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red

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~ 625 to 740 nm

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~ 480 to 405 THz

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orange

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~ 590 to 625 nm

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~ 510 to 480 THz

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yellow

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~ 565 to 590 nm

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~ 530 to 510 THz

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green

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~ 520 to 565 nm

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~ 580 to 530 THz

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cyan

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~ 500 to 520 nm

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~ 600 to 580 THz

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blue

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~ 430 to 500 nm

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~ 700 to 600 THz

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violet

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~ 380 to 430 nm

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~ 790 to 700 THz

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• Gas lasers
• HeNe (543 nm and 633 nm)
• Argon-Ion (458 nm, 488 nm or 514.5 nm)
• Carbon dioxide lasers (9.6 µm and 10.6 µm) used in industry for cutting and welding, up to 100 kW possible
• Carbon monoxide lasers, must be cooled, but extremely powerful, up to 500 kW possible
• Excimer gas lasers, producing ultraviolet light, used in semiconductor manufacturing and in LASIK eye surgery; F₂ (157 nm), ArF (193 nm), KrCl (222 nm), KrF (248 nm), XeCl (308 nm), XeF (351 nm)
• Commonly used laser types for dermatological procedures including removal of tattoos, birthmarks, and hair: ruby (694 nm), alexandrite (755 nm), pulsed diode array (810 nm), Nd:YAG (1064 nm), Ho:YAG (2090 nm), Er:YAG (2940 nm)
• Semiconductor laser diodes
• small: used in laser pointers, laser printers, and CD/DVD players
• bigger: large industrial diode lasers are available and used in industry for cutting and welding, power up to 10 kW is possible.
• Neodymium-doped YAG lasers (), a high-power laser operating in the infrared spectrum at 1064nm, used for cutting, welding and marking of metals and other materials also used in spectroscopy and for pumping dye lasers. Can be frequency doubled from 1064nm to 532nm to produce a green laser.
• Ytterbium-doped lasers with crystals such as Yb:YAG, Yb:KGW, Yb:KYW, Yb:SYS, Yb:BOYS, Yb:CaF2, or Yb-doped glasses (e.g. fibers); typically operating around 1020-1050 nm; potentially very high efficiency and high powers due to a small quantum defect; extremely high powers in ultrashort pulses can be achieved with Yb:YAG
• Erbium-doped YAG, 1645 nm
• Thulium-doped YAG, 2015 nm
• Holmium-doped YAG, 2096 nm, a efficient laser operating in the infrared spectrum, it is strongly absorbed by water-bearing tissues in sections less than a millimeter thick. It is usually operated in a pulsed mode, and passed through optical fiber surgical devices to resurface joints, remove rot from teeth, vaporize cancers, and pulverize kidney and gall stones.
• Titanium-doped sapphire () lasers, a highly tunable infrared laser, used for spectroscopy
• Erbium-doped fiber lasers, a type of laser formed from a specially made optical fiber, which is used as an amplifier for optical communications.
• External-cavity semiconductor lasers, e.g. for generating high power outputs with good beam quality, wavelength-tunable narrow-linewidth radiation, or ultrashort laser pulses
• Dye lasers
• Quantum cascade lasers
• Hollow cathode sputtering metal ion lasers, generating deep ultraviolet wavelengths, of which there are two examples; Helium-Silver (HeAg) 224 nm and Neon-Copper (NeCu) 248 nm. These lasers have particularly narrow oscillation linewidths of less than 0.01 cm^-1 making them good candidates for use in fluorescence supressed Raman spectroscopy.