The carbon dioxide (CO2) laser consists of a gas mixture that includes nitrogen, helium, carbon dioxide, xenon or water vapor and hydrogen in some cases. It is one of the earliest gas lasers to be developed by Kumar Patel in Bell Laboratory in 1964.
The gas mixture acts as a gain medium, and the laser is pumped through an electrical discharge. During electrical discharge, the nitrogen molecules are excited to their metastable vibrational state, and collide with the CO2 molecules to transfer their energy.
The CO2 laser can be operated in radio frequency range using AC/DC current. It emits infrared light at standard wavelengths of 9.6 and 10.6 µm. It is considered to be hazardous because of its high drive voltages and current. However, it is relatively safe at low intensities due to its long wavelength bands.
Due to their high power levels, CO2 lasers are commonly used in material processing applications, particularly for cutting die boards, metals, plastic, etc, welding metals such as copper, aluminum or stainless steel, and laser marking of different materials. They are applied in surgical procedures as water is capable of absorbing the wavelength of CO2 laser.
Other applications of CO2 laser include military rangefinding using LIDAR techniques and manufacturing of microfluidic devices.
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