Theoretical Research On The Threshold Behavior Of Damage In Laser Ablations Of Polymer

The phenomenon and mechanisms of polymer's laser damage are complicated because such materials do not show definite melting point and gasification temperature. In the process of photoablation, chemical reacation of organic material plays an important role. The ablation products are diverse, and ablation mechanism is very complicated. Researches on the polymer's laser ablation threshold not only deepen the understanding of the polymer's laser ablation, but also promote the application of polymer laser processingWith the date from a trust worth measurement of laser polyimide ablation, and based on Arrhenius surface temperature model, numerical analyses are performed to reveal some regularities in the process of polymer laser ablation. It is found that the ablation rate increases smoothly and exponentially with increasing fluence for 308nm, and 351nm wavelengths. Ablation is described in terms of a two-level system in which the excitation energy is dissipated via stimulated emission,thermal relaxation,and activated desorption of excited species. These results may be helpful for further study of the polymer laser damage threshold and promote the application of polymer laser processing in the sense of accurate determination of laser intensity.