A gas laser is a laser whose gain medium is a gas. The wavelengths emitted by gas lasers have high beam quality. Their powers depend on the gases and gas mixtures used. Gases used in gas lasers include helium, neon, argon, nitrogen, and carbon dioxide.
Helium-neon lasers emit light in diverse wavelengths. In the visible light range, the individual wavelengths are red with a wavelength of 632.8 nm, green with 543.5 nm, yellow with 594.1 nm and orange with 611.9 nm. In addition, there are He-Ne lasers that emit light in the infrared range. Their output powers range from a few milliwatts to several watts. They are used in interferometers, among other applications.
Argon-ion las ers work with the noble gas argon (Ar), which forms the gain medium as argon plasma. Argon lasers have output powers of up to 100 W. Emission-wise, they cover many wavelengths in the visible light range and ultraviolet UV light.
The same applies to the krypton ion laser as to the argon laser. They, too, can emit light at diverse wavelengths and have a relatively high output power.
Carbon dioxide lasers use carbon dioxide (CO2), helium and nitrogen (N2) as the gas mixture. Their emitted wavelength is in the long-wave infrared range between 9 µm and 11 µm, and their output power can be several kilowatts. Since their efficiency is about 10%, carbon dioxide lasers require relatively high supply powers.
Nitrogen lasers use nitrogen (N2) for light amplification. They operate in the ultraviolet range of an emitted wavelength of 337.1 nm. They have relatively good efficiency.