Nanometer-nanosecond dynamics in laser-induced expansion/contraction and ablation of polymer films

SD1, Equipment Development Division, Medical Systems Research & Development Center,

Research & Development Management Headquarters, FUJIFILMCorporation, 798 Miyanodai, Kaisei-machi,

Ashigarakamigun, Kanagawa 258-8538, Japan

Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University,

1001, Ta Hshueh Rd., Hsinchu 30010, Taiwan

Graduate School of Materials Science, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma,

Nara 630-0192, Japan

E-mail: masuhara@masuhara.jp, takuji_tada@fujifilm.co.jp

Manuscript received 14 December 2009, accepted 15 December 2009

In this account we have summarized our systematic studies on laser ablation and related phenomena of polymer films by utlilizing time-resolved absorption spectroscopy and nanosecond Interferometry. Polystyrene, poly(methyl methacrylate), poly(methyl acrylate), azobenzene-substituted urethane-urea copolymer, nitrocellulose, triazene polymer, polyurethane, and polyimide were examined, and their expansion and contraction dynamics were confirmed directly at the laser fluence below the ablation threshold. The molecular species which are formed by intense laser excitation are Identified by absorption spectroscopy and correlated to the morphological changes. We proposed the cyclic multiphotonic absorption mechanism and explained well 'the ablation and related phenomena In terms of photophysics and photochemistry.