argonlaser

An argon laser, or argon-ion laser, is a gas laser in which lasing transitions arise from argon ions in a sealed discharge tube. The tube is filled with argon gas, often with a small admixture of neon to improve pumping efficiency, and is excited by a high-voltage electrical discharge. The discharge creates a plasma that promotes argon ions to metastable states, from which photons are emitted as they decay. The principal lasing transitions occur in the blue-green region of the visible spectrum, with the strongest lines near 488 nanometers and 514.5 nanometers. Other, weaker lines in the blue and violet range also exist. The laser light is generated by an optical cavity formed by two mirrors, with one partially transmitting; continuous wave operation is common, and output powers typically range from fractions of a watt to tens of watts, depending on design. Argon lasers are usually water-cooled or forced-air cooled, and are relatively large and alignment-sensitive.

Applications are primarily in medicine and science. In ophthalmology, argon lasers are used for retinal photocoagulation and related procedures. In dermatology and microsurgery, they provide precise coagulation and cutting in tissue. In research and diagnostic settings, argon lasers serve as excitation sources for fluorescence microscopy and flow cytometry, particularly for fluorophores such as FITC that respond to the 488 nm line, and sometimes the 514.5 nm line is used for other dyes.

Compared with newer lasers, argon lasers are bulky and require substantial maintenance, and their niche relies on the stability and visibility of their blue-green lines. Safety measures are essential due to the exposure risk of visible laser radiation.

See also: helium-neon laser, krypton laser, diode laser.