Femtosecond and nanosecond laser damage thresholds of doped and undoped triazenepolymer thin films

The influence of pulse duration on the laser-induced damage in undoped or infrared-absorbing-dye doped thin triazenepolymer films on glass substrates has been investigated for single, near-infrared (800 nm) Ti:sapphire laser pulses with durations ranging from 130 fs up to 540 fs and complementarily for infrared (1064 nm) Nd:YAG ns-laser single-pulse irradiation. The triazenepolymer material has been developed for high resolution ablation with irradiation at 308 nm. Post-irradiation optical microscopy observations have been used to determine quantitatively the threshold fluence for permanent laser damage. In contrast to our previous studies on a triazenepolymer with different composition [J. Bonse, S.M. Wiggins, J. Solis, T. Lippert, Appl. Surf. Sci. 247 (2005) 440], a significant dependence of the damage threshold on the pulse duration is found in the sub-picosecond regime with values ranging from similar to 500 mJ/cm(2) (130 fs) up to similar to 1500 mJ/cm(2) (540 fs). Other parameters such as the film thickness (50 nm and 1.1 mu m samples) or the doping level show no significant influence on the material behavior upon irradiation. The results for fs- and ns-laser pulse irradiation are compared and analyzed in terms of existent ablation models. (c) 2007 Elsevier B.V. All rights reserved.