Spectroscopic investigation of fs laser-induced defects in polymer and crystal media

摘要

We investigated formation of defects in four polymers namely Poly (methylmethacrylate) [PMMA], Poly dimethylsiloxane [PDMS], Polystyrene [PS], and Polyvinyl alcohol [PVA] and crystal media such as Lithium Niobate [LiNbO_3]. Spectroscopic studies of the femtosecond (fs) laser modified regions were systematically performed after fabricating several gratings and micro-channels. We observed emission from the fs laser modified regions of these polymers when excited at different wavelengths. Pristine polymers are not paramagnetic, but exhibited paramagnetic behavior upon fs irradiation. LiNbO_3 (LNB) crystal has not shown any defect formation upon laser irradiation. Confocal micro-Raman studies were also performed to establish the formation of defects.