Lasermedier

Lasermedier, or laser media, are the materials that provide optical gain in lasers by undergoing stimulated emission. They act as the gain medium of a laser and determine the emission wavelength, efficiency, and overall performance. A lasermedium must support population inversion and offer a sufficiently high stimulated emission cross-section to amplify light traveling through it.

Lasing media are commonly grouped into four broad classes. Solid-state lasers use a crystalline or glass host doped with active ions, such as Nd:YAG, Er:YAG, or Yb:YAG, where laser action occurs at characteristic infrared wavelengths. Gas lasers employ a gaseous mixture (for example CO2, He-Ne, or N2O) and often provide high beam quality and power. Dye lasers use organic dye solutions or dye-doped polymers and offer broad tunability across visible and near-infrared regions. Semiconductor lasers (diode lasers) rely on quantum wells or quantum dots in a semiconductor junction and are compact, efficient, and widely used for communication and sensing.

Key properties of lasermedier include the emission wavelength, the stimulated emission cross-section, the gain coefficient, and the lifetime of the excited state. Pumping methods—optical pumping with light sources, electrical pumping, or gas discharge—are used to achieve population inversion. Thermal management, material purity, and dopant concentration affect efficiency and beam quality.

Examples illustrate the range of lasermedier: Nd:YAG emits around 1064 nm; CO2 lasers operate near 10.6 µm; dye lasers cover broad tunability in the visible region; semiconductor lasers emit from near-infrared to mid-infrared wavelengths. The choice of medium depends on desired wavelength, power, efficiency, and application.