Sensitized implantation of fluorescent molecules in a polymer film by near-infrared laser irradiation: comparison with direct ultraviolet-laser implantation

A polymer film doped both with a fluorescent coumarin derivative and an infrared absorbing dye was overlaid with a neat polymer film and then irradiated with 1064 nm laser pulses passing through the neat film. The unbroken coumarin dye was demonstrated to be transferred to the neat film surface, which however led to the formation of submicroscopic crystalline powder by repetitive irradiation. The result was compared with that of direct ultraviolet-laser irradiation, which resulted in rather homogeneous fluorescent patterns by repetitive irradiation. Characteristics of the sensitized implantation were discussed in connection with the mechanism of laser-induced molecular implantation. q1999 Elsevier Science B.V. All rights reserved.