CO2Laser

A CO2 laser is a gas laser in which the lasing medium is a mixture of carbon dioxide, nitrogen, helium, and small amounts of water vapor. The primary emission is in the infrared, near a wavelength of 10.6 micrometers, with a secondary line around 9.6 μm; some designs use the 10.3 μm line. Electrical discharge excites the CO2 molecules, and energy transfer from nitrogen helps achieve population inversion while helium serves as a buffer gas and cooling agent. The laser light is produced in a gas-filled tube bounded by mirrors in a resonator and is typically emitted in continuous wave or pulsed operation. Modern CO2 lasers may be sealed or RF-excited, and high-peak-power pulsed variants such as TEA CO2 lasers are used for short-duration pulses.

The long infrared wavelength leads to strong absorption in water-containing materials, enabling precise ablation with limited thermal diffusion beyond the target area. This makes CO2 lasers well suited for materials processing, including cutting, engraving, drilling, and welding of polymers, wood, paper, textiles, glass, ceramics, and some composites. They are also used in medicine and cosmetic surgery for soft-tissue ablation and resurfacing, often delivered through a focusing nozzle or specialized optics.

Compared with many solid-state lasers, CO2 lasers are less effective for direct cutting of metals because metals reflect infrared light at this wavelength; processing metal often requires alternative technologies or process aids. Advantages of CO2 lasers include high output power and good beam quality, while limitations include the size and complexity of the equipment, the need for gas supplies and cooling, and safety considerations due to intense infrared radiation.