A comparative examination of photoproducts formed in the 248 and 193 nm ablation of doped PMMA

A comparative examination of the photoproducts formed in the 193 and 248 nm ablation of PMMA doped with the highly photodissociable iodo-naphthalene i s presented. To this end, laser-induced fluorescence is employed to probe t he dopant-derived emitting photoproducts that remain in the substrate follo wing ablation. It is found that the emitting products formed at these two w avelengths are qualitatively the same. However, the dependence of the amoun t of the photoproduct remaining in the substrate on laser fluence differs. In the case of the ablation at 248 mn, there is a sharp increase in the pho toproduct amount, whereas in the ablation at 193 nm, the remaining photopro duct quantity is smaller than that expected on the basis of the Linear depe ndence observed at lower fluences. Plausible explanations for these differe nces are advanced. (C) 2001 Elsevier Science B.V. All rights reserved.