A dye laser can be considered as a special device to convert electromagnetic radiation from one wavelength, to another wavelength which can be tuned.

The output of a dye laser is always a coherent radiation tunable over a specific spectrum region, determined by the Dye material.

History:
Dye laser was first demonstrated in 1965 at IBM laboratories in the US, by Peter P. Sorokin and J. R. Lankard.

They discovered the dye laser action during a fluorescence research of organic dye molecules, which were excited by Ruby laser.

In 1967 scientists discovered the possibility to tune the emitted wavelength, using a grating at the end of the optical cavity.