Abstract
Laser ablation of polymeric materials sensitized with aromatic compounds has been studied with various time-resolved measurement techniques. Nanosecond imaging revealed the time scale of solid polymer ejection. Transient thermal expansion of polymer was unveiled by a newly developed interferometric method. Time-resolved absorption and emission spectroscopies showed that aromatic sensitizers hardly decomposed but instead indicated hot domain formation in the polymer matrix. Intact sensitizer molecules were detected by time of flight mass spectrometry, and their velocity distribution suggested that the polymer surface was heated up to around 600 K at the ablation threshold. Light absorption dynamics is explained in terms of the repetition of excitation and relaxation in electronic excited states of sensitizer molecules. The generation of transient hot domain in polymer is considered to lead sensitized ablation.
