Ablation thresholds and morphological changes of poly‐l‐lactic acid for pulse durations in the femtosecond‐to‐picosecond regime

Abstract

Biodegradable polymers such as poly‐l‐lactic acid (PLLA) are essential tools for a wide range of medical applications because of their mechanical robustness and bio‐affinity. Laser processing is commonly used to construct various structures from biodegradable polymers. However, in general, polymers deteriorate rapidly owing to laser‐induced heating effects. In this study, we investigate the optimum irradiation conditions for PLLA processing, using an ultrafast laser and finely controlling the pulse duration over the femtosecond‐to‐picosecond range. We report on the morphological characteristics of the craters generated by single‐shot and multiple‐shot laser irradiation under pulse duration control. Our results show that crater morphology and damage threshold in the single‐shot regime depend on pulse duration and that the degree of crater unevenness is insensitive to pulse duration in the multishot regime.