Organic dyes typically used dissolved in an organic solvent. The dye solution is circulated
continuously through the
laser chamber of the
dye laser, in which it is excited (pumped) by
flash lamps or by another
laser.
Source:
PAC, 2007, 79, 293
(Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006))
on page 362