Abstract
In recent years, processing with femtosecond lasers has attracted much attention for realizing precise
manufacturing because they are less influenced by the thermal heating of a material. In this study, the
pulse-to-pulse initial dynamics of femtosecond laser ablation processes were visualized using single-shot
ultrafast terahertz time-domain spectroscopy. After each laser pulse, the resultant depth profile of the
target surface was observed using line field spectral domain optical coherence tomography.
Simultaneous measurement of the pulse-to-pulse terahertz radiation waveforms and depth profiles of the
ablated surface revealed that observing the initial excitation process is essential for understanding the
subsequent complex and multiscale spatiotemporal dynamics of the femtosecond laser ablation processes.
