MULTIPHOTON ABSORPTION IN ORGANIC-DYE SOLUTIONS

Two-photon absorption in organic dyes can be enhanced by orders of mag nitude in particular situations. An original model accounting for an e nhanced nonlinear absorption in concentrated interacting dye solutions is presented. The related nonlinear absorption which is induced in th e transparency region of the dye solutions has an intensity dependent avalanche behavior. It may reach levels as high as using conventional excited state absorption. This opens new possibilities for the practic al use of two-photon absorption. (C) 1998 Published by Elsevier Scienc e B.V.