Tunable lasers use the same methods as their non-tunable counterparts to convert input pump light from flash lamps or pump lasers into laser outputs. The major advantage of tunable lasers, from which all the other desirable properties stem, is that their wavelengths that can be varied over a range of values.
Dye lasers use the lasing properties of some organic dyes to produce a group of lasers that covers the largest range of wavelengths. They are still the most common form of tunable laser.
These lasers use doped crystalline or amorphous solids to imitate the properties of the dye lasers above.