Delay-Selected Energy Coupling and Ablation Enhancement in Femtosecond Double-Pulse Irradiation of Aluminum
- 1College of Control Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China
- 2Sinopec Petroleum Engineering Corporation, Dongying 257026, China
- 3School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350108, China
Abstract
We investigate the effect of inter-pulse delay on femtosecond laser ablation of thin aluminum films using a dual-pulse setup at 800 nm with precisely controlled temporal separation. The ablation threshold, measured by an extrapolation method, first decreases and then increases with delays, reaching a minimum at ~1 ps. To reveal the underlying mechanism, time-resolved pump–probe reflection microscopy at 400 nm is employed. The transient reflectivity exhibits an ultrafast drop upon excitation, attributed to enhanced intraband absorption arising from Fermi smearing in the sp-band. At delays near 1 ps, a clear inflection in the reflectivity transient indicates the onset of surface thermal expansion and density reduction, which impedes efficient energy deposition into deeper material by the second pulse, thus lowering the ablation threshold. These results provide direct time-resolved evidence linking transient thermomechanical responses to delayed ablation threshold in femtosecond laser processing of aluminum.
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BibTeX
@article{wang2026delayselected,
title = {{Delay-Selected Energy Coupling and Ablation Enhancement in Femtosecond Double-Pulse Irradiation of Aluminum}},
author = {Feifei Wang and Jiaxuan Liu and Kai Sun and Yimo Liu and Zhe Peng and Yuntao Lang and Yueyuan Liu and Changji Pan},
journal = {Molecules},
year = {2026},
month = oct,
doi = {10.3390/molecules31213894},
url = {https://www.mdpi.com/1420-3049/31/21/3894},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Delay-Selected Energy Coupling and Ablation Enhancement in Femtosecond Double-Pulse Irradiation of Aluminum
AU - Feifei Wang
AU - Jiaxuan Liu
AU - Kai Sun
AU - Yimo Liu
AU - Zhe Peng
AU - Yuntao Lang
AU - Yueyuan Liu
AU - Changji Pan
PY - 2026
DA - 2026/10/28
JO - Molecules
DO - 10.3390/molecules31213894
UR - https://www.mdpi.com/1420-3049/31/21/3894
AB - We investigate the effect of inter-pulse delay on femtosecond laser ablation of thin aluminum films using a dual-pulse setup at 800 nm with precisely controlled temporal separation. The ablation threshold, measured by an extrapolation method, first decreases and then increases with delays, reaching a minimum at ~1 ps. To reveal the underlying mechanism, time-resolved pump–probe reflection microscopy at 400 nm is employed. The transient reflectivity exhibits an ultrafast drop upon excitation, attributed to enhanced intraband absorption arising from Fermi smearing in the sp-band. At delays near 1 ps, a clear inflection in the reflectivity transient indicates the onset of surface thermal expansion and density reduction, which impedes efficient energy deposition into deeper material by the second pulse, thus lowering the ablation threshold. These results provide direct time-resolved evidence linking transient thermomechanical responses to delayed ablation threshold in femtosecond laser processing of aluminum.
SN - 1420-3049
ER -