Dye lasers were independently discovered by P. P. Sorokin and F. P. Schäfer (and colleagues) in 1966.
In addition to the usual liquid state, dye lasers are also available as solid state dye lasers (SSDL). SSDL use dye-doped organic matrices as gain medium.
A dye laser consists of an organic dye mixed with a solvent, which may be circulated through a dye cell, or streamed through open air using a dye jet. A high energy source of light is needed to "pump" the liquid beyond its lasing threshold. A fast discharge flashlamp or an external laser is usually used for this purpose. Mirrors are also needed to oscillate the light produced by the dye’s fluorescence, which is amplified with each pass through the liquid. The output mirror is normally around 80% reflective, while all other mirrors are usually more than 99% reflective. The dye solution is usually circulated at high speeds, to help avoid triplet absorption and to decrease degradation of the dye. A prism or diffraction grating is usually mounted in the beam path, to allow tuning of the beam.
A ring laser design is often chosen for continuous operation, although a Fabry–Pérot design is sometimes used. In a ring laser, the mirrors of the laser are positioned to allow the beam to travel in a circular path. The dye cell, or cuvette, is usually very small. Sometimes a dye jet is used to help avoid reflection losses.
The dye is usually pumped with an external laser, such as a nitrogen, excimer, or frequency doubled Nd:YAG laser. The liquid is circulated at very high speeds, to prevent triplet absorption from cutting off the beam. Unlike Fabry–Pérot cavities, a ring laser does not generate standing waves which cause spatial hole burning, a phenomenon where energy becomes trapped in unused portions of the medium between the crests of the wave. This leads to a better gain from the lasing medium.