Our collaborative research with Nikon on the early stages of femtosecond laser ablation has been published in Journal of Applied Physics and selected as a Featured Article. Using single‑shot terahertz spectroscopy, which enables real‑time measurement of terahertz waveforms, together with optical coherence tomography for surface‑profile imaging, we captured both the terahertz waveforms emitted on a pulse‑by‑pulse basis and the resulting ablation geometry. These measurements reveal that the terahertz emission reflects the initial charge‑emission dynamics, which in turn govern the final ablation outcome. This finding provides an important foundation for advancing our understanding of the ultrafast early processes in femtosecond‑laser ablation.

Link: https://pubs.aip.org/aip/jap/article/140/4/043111/3399603/Ultrafast-charge-emission-at-terahertz-frequency