What is a Gas Laser?

Various types of lasers use a specific gas as the gain medium. Although different gas lasers exhibit significant differences in working principles, wavelengths, efficiency, and power, they still share several common characteristics:

1. Pumped via Ionization Discharge: Most gas lasers are pumped through electric discharge, requiring a high-voltage power supply and usually high-power input.

2. High Optical Gain and Low Beam Distortion: Despite the low density of gases, they can produce high optical gain due to their large emission cross-sections. Conversely, beam distortion caused by the gas is typically minimal.

3. Stability and Lifetime Constraints: Gas is a fairly stable gain medium, not prone to cracking or defects common in solid-state media. However, during operation, the gas may undergo chemical modification or become contaminated, leading to a limited service life—especially for gas lasers requiring high current densities.

Important Gas Lasers and Their Characteristics:

• Helium-Neon (HeNe) Laser: Provides milliwatt-level visible or infrared laser light, typically characterized by a narrow linewidth and high frequency stability.

• Argon-Ion and Krypton-Ion Lasers: Provide several watts of visible laser light with high beam quality, though power efficiency is relatively low.

• Carbon Dioxide CO2 Laser: A highly efficient 10.6 µm light source, widely used in material processing.

• Excimer Laser: A high-power pulsed ultraviolet (UV) laser.