A gas laser is a type of laser that uses a gas as its medium to produce light. In these lasers, an electrical current or another energy source excites the gas molecules, causing them to emit photons. Common gases used include helium, neon, and carbon dioxide. The emitted light is typically coherent, meaning the light waves are in phase and can travel long distances without spreading out. Gas lasers are known for their efficiency and ability to produce high-quality beams. They are widely used in various applications, including medical procedures, industrial cutting, and scientific research. The versatility of gas lasers makes them valuable tools in many fields.