The fluorescence lifetime of fluorescent materials in solution is often measured in the case of low concentration. But the medium of dye laser is always high concentration solution

generally in ihe range of 10

-4

~10

-2

mol·L

-1

. It is necessary to measure the parameters

such as quantum yield and fluorescence lifetime

of high concentration solution in order to studying the physical and chemical behaviors of the laser dye. However

it is difficult to accurately measure the fluorescence lifetime because of the existance of self-absorption and re-emission of the fluorescence molecules in high concentration solution.Recently

several authors have developed some methods for measuring the fluorescence lifetime of high concentration solutions.