Abstract

We have analyzed the influence of the temporal pulse shape on femtosecond (fs) laser-induced surface ablation processes in sapphire. To this end, single transform-limited (TL), stretched, and third-order-dispersion (TOD) shaped fs pulses have been used, while the dynamics of the interaction were analyzed by fs-resolved microscopy and correlated with plasma emission intensity and crater morphology. The modification of the pulse shape enables changing the ablation mechanism from a strong, thermally mediated ablation process to a gentle ablation process mediated by Coulomb explosion (CE), with respective ablation depths of 100–200 nm and 5–10 nm. Analysis of the transient optical response allows direct comparison of the transient plasma carrier densities involved, observing comparable peak values for both processes. For strong ablation induced by TL pulses, a direct relation between plasma density and local ablation depth is found, but this does not hold for the CE-mediated process observed for TOD-shaped pulses. For TOD-shaped pulses at very high fluence, a different ablation mechanism involving explosive boiling is identified. This mechanism leads to the formation of deep craters with reduced lateral extension and steep walls. This amount of control over the ablation mechanisms by a simple selection of the pulse shape should be of interest for new surface structuring approaches.

© 2014 Optical Society of America

Full Article  |  PDF Article
OSA Recommended Articles
Dynamics of plasma formation, relaxation, and topography modification induced by femtosecond laser pulses in crystalline and amorphous dielectrics

D. Puerto, J. Siegel, W. Gawelda, M. Galvan-Sosa, L. Ehrentraut, J. Bonse, and J. Solis
J. Opt. Soc. Am. B 27(5) 1065-1076 (2010)

Plasma evolution during metal ablation with ultrashort laser pulses

J. König, S. Nolte, and A. Tünnermann
Opt. Express 13(26) 10597-10607 (2005)

Enhancing the expansion of a plasma shockwave by crater-induced laser refocusing in femtosecond laser ablation of fused silica

Qingsong Wang, Lan Jiang, Jingya Sun, Changji Pan, Weina Han, Guoyan Wang, Hao Zhang, Costas P. Grigoropoulos, and Yongfeng Lu
Photon. Res. 5(5) 488-493 (2017)

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (5)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Tables (1)

You do not have subscription access to this journal. Article tables are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Equations (1)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Metrics

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription