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A gas laser is a laser in which an electric current is discharged through a gas to produce coherent light. The gas laser was the first continuous-light laser and the first laser to operate on the principle of converting electrical energy to a laser light output. The first gas laser, the Helium–neon laser (HeNe), was co-invented by Iranian-American physicist Ali Javan and American physicist William R. Bennett, Jr., in 1960. It produced a coherent light beam in the infrared region of the spectrum at 1.15 micrometres.

Types of gas laser

Gas lasers using many gases have been built and used for many purposes.

Carbon dioxide lasers, or CO2 lasers can emit hundreds of kilowatts[1] at 9.6 µm and 10.6 µm, and are often used in industry for cutting and welding. The efficiency of a CO2 laser is over 10%.

Carbon monoxide or "CO" lasers have the potential for very large outputs, but the use of this type of laser is limited by the toxicity of carbon monoxide gas. Human operators must be protected from this deadly gas. Furthermore, it is extremely corrosive to many materials including seals, gaskets, etc.

Helium–neon (HeNe) lasers can be made to oscillate at over 160 different wavelengths by adjusting the cavity Q to peak at the desired wavelength. This can be done by adjusting the spectral response of the mirrors or by using a dispersive element (Littrow prism) in the cavity. Units operating at 633 nm are very common in schools and laboratories because of their low cost and near perfect beam qualities.

Nitrogen lasers operate in the ultraviolet range, typically 337.1 nm, using molecular nitrogen as its gain medium, pumped by an electrical discharge.

TEA lasers are energized by a high voltage electrical discharge in a gas mixture generally at or above atmospheric pressure. The acronym "TEA" stands for Transversely Excited Atmospheric.
Chemical lasers
Main article: Chemical laser

Chemical lasers are powered by a chemical reaction, and can achieve high powers in continuous operation. For example, in the hydrogen fluoride laser (2.7–2.9 µm) and the deuterium fluoride laser (3.8 µm) the reaction is the combination of hydrogen or deuterium gas with combustion products of ethylene in nitrogen trifluoride. They were invented by George C. Pimentel.

Chemical lasers are powered by a chemical reaction permitting a large amount of energy to be released quickly. Such very high power lasers are especially of interest to the military. Further, continuous wave chemical lasers at very high power levels, fed by streams of gasses, have been developed and have some industrial applications.
Excimer lasers
Main article: Excimer laser

Excimer lasers are powered by a chemical reaction involving an excited dimer, or excimer, which is a short-lived dimeric or heterodimeric molecule formed from two species (atoms), at least one of which is in an excited electronic state. They typically produce ultraviolet light, and are used in semiconductor photolithography and in LASIK eye surgery. Commonly used excimer molecules include F2 (fluorine, emitting at 157 nm), and noble gas compounds (ArF [193 nm], KrCl [222 nm], KrF [248 nm], XeCl [308 nm], and XeF [351 nm]).[2]
Ion lasers
Main article: Ion laser

Argon-ion lasers emit light in the range 351–528.7 nm. Depending on the optics and the laser tube a different number of lines is usable but the most commonly used lines are 458 nm, 488 nm and 514.5 nm.
Metal-vapor lasers

Metal-vapor lasers are gas lasers that typically generate ultraviolet wavelengths. Helium-silver (HeAg) 224 nm neon-copper (NeCu) 248 nm and helium-cadmium (HeCd) 325 nm are three examples. These lasers have particularly narrow oscillation linewidths of less than 3 GHz (500 femtometers),[3] making them candidates for use in fluorescence suppressed Raman spectroscopy.

The Copper vapor laser, with two spectral lines of green (510.6 nm) and yellow (578.2 nm), is the most powerful laser with the highest efficiency in the visible spectrum.[4]

High volume of active material
Active material is relatively inexpensive
Almost impossible to damage the active material
Heat can be removed quickly from the cavity


He-Ne laser is mainly used in making holograms.
In laser printing He-Ne laser is used as a source for writing on the photosensitive material.
He-Ne lasers were used in reading Bar Codes, which are imprinted on products in stores. They have been largely replaced by laser diodes.
Nitrogen lasers and excimer laser are used in pulsed dye laser pumping.[5]
Ion lasers, mostly argon, are used in CW dye laser pumping.[5]

See also

Gas dynamic laser
Brewster window
List of laser types


"Air Force Research Lab's high power CO2 laser". Defense Tech Briefs. Archived from the original on 2007-06-07.
Schuocker, D. (1998). Handbook of the Eurolaser Academy. Springer. ISBN 0-412-81910-4.
"Deep UV Lasers" (PDF). Photon Systems, Covina, Calif. Archived from the original (PDF) on 2007-07-01. Retrieved 2007-05-27.
Endo, Masamori; Walter, Robert F. (3 October 2018). Gas Lasers. p. 451. ISBN 9781420018806.

Duarte, F. J. (2003). Tunable Laser Optics. Elsevier Academic. ISBN 0-12-222696-8.

Yariv, Amnon (1989). Quantum Electronics (3rd ed.). Wiley. ISBN 0-471-60997-8.
http://www.google.com/patents/about?id=r2pmAAAAEBAJ&dq=3,149,290 Patent #3,149,290


Gas lasers

Carbon dioxide Carbon monoxide Helium–neon Nitrogen TEA laser Asterix IV laser ISKRA4,5

Distinct subtypes:

Chemical laser Excimer laser Ion laser Metal-vapor laser

Laser types: Solid-state
Semiconductor Dye Gas
Chemical Excimer Ion Metal Vapor



List of laser articles List of laser types List of laser applications Laser acronyms

Laser types: Solid-state
Semiconductor Dye Gas
Chemical Excimer Ion Metal Vapor

Laser physics

Active laser medium Amplified spontaneous emission Continuous wave Doppler cooling Laser ablation Laser cooling Laser linewidth Lasing threshold Magneto-optical trap Optical tweezers Population inversion Resolved sideband cooling Ultrashort pulse

Laser optics

Beam expander Beam homogenizer B Integral Chirped pulse amplification Gain-switching Gaussian beam Injection seeder Laser beam profiler M squared Mode-locking Multiple-prism grating laser oscillator Multiphoton intrapulse interference phase scan Optical amplifier Optical cavity Optical isolator Output coupler Q-switching Regenerative amplification

Laser spectroscopy

Cavity ring-down spectroscopy Confocal laser scanning microscopy Laser-based angle-resolved photoemission spectroscopy Laser diffraction analysis Laser-induced breakdown spectroscopy Laser-induced fluorescence Noise-immune cavity-enhanced optical heterodyne molecular spectroscopy Raman spectroscopy Second-harmonic imaging microscopy Terahertz time-domain spectroscopy Tunable diode laser absorption spectroscopy Two-photon excitation microscopy Ultrafast laser spectroscopy

Laser ionization

Above-threshold ionization Atmospheric-pressure laser ionization Matrix-assisted laser desorption/ionization Resonance-enhanced multiphoton ionization Soft laser desorption Surface-assisted laser desorption/ionization Surface-enhanced laser desorption/ionization

Laser fabrication

Laser beam welding Laser bonding Laser converting Laser cutting Laser cutting bridge Laser drilling Laser engraving Laser-hybrid welding Laser peening Multiphoton lithography Pulsed laser deposition Selective laser melting Selective laser sintering

Laser medicine

Computed tomography laser mammography Laser capture microdissection Laser hair removal Laser lithotripsy Laser coagulation Laser surgery Laser thermal keratoplasty LASIK Low-level laser therapy Optical coherence tomography Photorefractive keratectomy Photorejuvenation

Laser fusion

Argus laser Cyclops laser GEKKO XII HiPER ISKRA lasers Janus laser Laboratory for Laser Energetics Laser integration line Laser Mégajoule Long path laser LULI2000 Mercury laser National Ignition Facility Nike laser Nova (laser) Novette laser Shiva laser Trident laser Vulcan laser

Civil applications

3D laser scanner CD DVD Blu-ray Laser lighting display Laser pointer Laser printer Laser tag

Military applications

Advanced Tactical Laser Boeing Laser Avenger Dazzler (weapon) Electrolaser Laser designator Laser guidance Laser-guided bomb Laser guns Laser rangefinder Laser warning receiver Laser weapon LLM01 Multiple Integrated Laser Engagement System Tactical High Energy Laser Tactical light ZEUS-HLONS (HMMWV Laser Ordnance Neutralization System)

Physics Encyclopedia



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