A comparative study of the photochemical modifications effected in the UV laser ablation of doped polymer substrates

The photochemical modifications induced by excimer 248 nm ablation of PMMA films doped with organic compounds exemplifying different photoreactivities are presented. The employed dopants were naphthalene and the photosensitiv e bromo- and iodonaphthalene. The comparison of the three systems shows tha t ablation with nanosecond (30 ns) pulses results in significant modificati ons of the photosensitive halonaphthalene dopants, including an increase in their photolysis yields and the formation of additional products. In sharp contrast, in the ablation with 500 fs pulses, photochemical modifications are found to be limited. (C) 2000 Elsevier Science B.V. All rights reserved .