Ablation mechanism in underwater drilling by an ultrafast laser with pulse energy below the water breakdown threshold

2022 ◽  
Vol 73 ◽  
pp. 354-363
Author(s):  
Changlong Zheng ◽  
Hong Shen
2000 ◽  
Author(s):  
J. Sun ◽  
J. P. Longtin ◽  
P. M. Norris

Abstract Silica aerogels are unique nanostructured materials that possess many distinctive qualities, including extremely low densities and thermal conductivities, very high surface-area-to-volume ratios, and large strength-to-weight ratios. Aerogels, however, are very brittle, and are not readily shaped using traditional machining operations. Ultrafast laser processing may provide an alternative for precision shaping and machining of these materials. This paper discusses investigations of ultrafast laser machining of aerogels for material removal and micromachining. The advantages of ultrafast laser processing include a minimal thermal penetration region and low processing temperatures, precision removal of material, and good-quality feature definition. In this work, an amplified femtosecond Ti:sapphire laser system is used to investigate the breakdown threshold, material removal rate, and specific issues associated with laser processing of aerogels, as well as recommendations for further investigations for these unique materials.


2020 ◽  
Vol 92 (2) ◽  
pp. 20701
Author(s):  
Bo Li ◽  
Xiaofeng Li ◽  
Zhifeng Zhu ◽  
Qiang Gao

Laser-induced breakdown spectroscopy (LIBS) is a powerful technique for quantitative diagnostics of gases. The spatial resolution of LIBS, however, is limited by the volume of plasma. Here femtosecond-nanosecond dual-pulsed LIBS was demonstrated. Using this method, the breakdown threshold was reduced by 80%, and decay of continuous radiation was shortened. In addition, the volume of the plasma was shrunk by 85% and hence, the spatial resolution of LIBS was significantly improved.


2021 ◽  
Vol 33 (1) ◽  
pp. 012009
Author(s):  
Aiko Narazaki ◽  
Hideyuki Takada ◽  
Dai Yoshitomi ◽  
Kenji Torizuka ◽  
Yohei Kobayashi

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