Description of a Co2 Laser
The CO2 gas laser is one of the oldest and most common types of lasers in the world. The first CO2 laser was built by Kumar Patel in 1964, at Bell Labs in New Jersey. CO2 lasers are used today in many industrial capacities.
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Components
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Like any laser, a CO2 laser's primary components are mirrors and an energy source. Like all gas lasers, these mirrors are positioned inside a tube (called a "gas discharge tube"), which is filled with a gas mixture. In most CO2 lasers, this mixture is about 20 percent carbon dioxide (CO2), 20 percent nitrogen (N2), a small amount of Hydrogen (H2) or Xenon (Xe), and a large amount of helium (He).
Construction
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The mirrors used in CO2 lasers must be built out of special materials, since the laser itself operates in the infrared spectrum. Mirrors are made of silicon, molybdenum or gold, while lenses are often constructed out of zinc selenide. In many cases, however, these components are made from diamonds, which are the most durable of the available materials. The output of a given CO2 laser can be anywhere from milliwatts (mW) to kilowatts (kW).
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Operation
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In a CO2 laser, the introduction of energy to the gases causes the nitrogen atoms in the mixture to vibrate. As the nitrogen collides with the carbon dioxide in the mixture, the carbon dioxide becomes excited. This generates the energy needed for "population inversion," a process that ultimately generates the laser's output.
Applications
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CO2 lasers are usually used in industrial settings for cutting and welding. Low-powered CO2 lasers are sometimes used for engraving and are increasingly being used in surgical procedures. Israeli researchers have recently experimented with CO2 lasers to seal wounds or surgical incisions instead of using traditional stitches or sutures. Finally, the military uses special types of CO2 lasers for range-finding.
Homemade CO2 Lasers
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Many amateur hobbyists (and scientists) have built their own CO2 lasers for personal use. This is not necessarily cheap or easy -- especially if you are unfamiliar with lasers and chemistry. For aspiring laser manufacturers, there are guides available online, the most prominent of which is Sam's Laser FAQ (see below for link).
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References
Resources
- Photo Credit Tobo at Creativecommons.org
