A gas laser is a type of laser that utilizes a gaseous medium as the active medium to produce coherent and amplified light. The gaseous medium in a gas laser can consist of various gases, including helium, neon, argon, krypton, carbon dioxide, and nitrogen, among others. These gases are enclosed within a glass or metal tube known as a laser cavity, which is usually filled with high-pressure gas to facilitate the laser operation.
Gas lasers operate by stimulating the gas atoms or molecules to emit light photons. This is achieved by using an external energy source, such as an electric discharge, optical pumping, or even chemical reactions, to excite the gas particles to higher energy states. As the excited gas atoms or molecules return to their lower energy states, they emit photons that have the same frequency and are in phase, resulting in coherent light.
Gas lasers can emit laser beams in a wide range of wavelengths, making them useful in various scientific, industrial, medical, and technological applications. Some common types of gas lasers include helium-neon lasers, argon ion lasers, carbon dioxide lasers, and excimer lasers, each with its own specific characteristics and applications.
Gas lasers are known for their high power output, excellent beam quality, and relatively longer coherence lengths compared to other types of lasers. They are widely used in applications such as laser cutting, laser welding, laser lithography, medical procedures (e.g., laser eye surgery), scientific research, and laser-based displays.
