Breakdown of spallation in multi-pulse ultrafast laser ablation
Fuente:
arXiv
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2026
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866915938661564416 |
|---|---|
| author | Redka, David Vollmann, Julian Thomae, Nicolas Spellauge, Maximilian Huber, Heinz P. |
| author_facet | Redka, David Vollmann, Julian Thomae, Nicolas Spellauge, Maximilian Huber, Heinz P. |
| contents | Ultrashort-pulse laser ablation of metals near damage threshold is governed by homogeneous spallation, in which tensile unloading releases a nanometre-thin liquid film whose optical signatures are temporally evolving concentric Newton rings in pump--probe experiments. This well-established picture rests almost exclusively on single-pulse results obtained on ideally flat surfaces, yet application-oriented processing invariably operates in a multi-pulse regime in which each pulse irradiates a surface progressively modified by preceding pulses. Whether homogeneous spallation persists under these conditions has remained an open question. Here we resolve this question using time-resolved pump-probe interferometry applied pulse by pulse to austenitic stainless steel. We show that homogeneous spallation dominates the first pulse, while its contribution is strongly reduced for the second pulse. By the third pulse, Newton rings vanish and sustained surface bulging collapses, with the optical transients fully saturating into a phase-explosion-like signature by the fourth pulse. Fourier-domain coherence analysis rules out roughness-induced decoherence as an optical artefact. Four independent observables, spanning time-resolved and final-state measurements, converge on the same transition after three to four pulses. Spallation-layer formation, widely invoked to explain ultrashort-pulse ablation of metals, is thus a single-pulse phenomenon rather than a multi-pulse ablation mechanism. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2604_13858 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Breakdown of spallation in multi-pulse ultrafast laser ablation Redka, David Vollmann, Julian Thomae, Nicolas Spellauge, Maximilian Huber, Heinz P. Optics Materials Science Ultrashort-pulse laser ablation of metals near damage threshold is governed by homogeneous spallation, in which tensile unloading releases a nanometre-thin liquid film whose optical signatures are temporally evolving concentric Newton rings in pump--probe experiments. This well-established picture rests almost exclusively on single-pulse results obtained on ideally flat surfaces, yet application-oriented processing invariably operates in a multi-pulse regime in which each pulse irradiates a surface progressively modified by preceding pulses. Whether homogeneous spallation persists under these conditions has remained an open question. Here we resolve this question using time-resolved pump-probe interferometry applied pulse by pulse to austenitic stainless steel. We show that homogeneous spallation dominates the first pulse, while its contribution is strongly reduced for the second pulse. By the third pulse, Newton rings vanish and sustained surface bulging collapses, with the optical transients fully saturating into a phase-explosion-like signature by the fourth pulse. Fourier-domain coherence analysis rules out roughness-induced decoherence as an optical artefact. Four independent observables, spanning time-resolved and final-state measurements, converge on the same transition after three to four pulses. Spallation-layer formation, widely invoked to explain ultrashort-pulse ablation of metals, is thus a single-pulse phenomenon rather than a multi-pulse ablation mechanism. |
| title | Breakdown of spallation in multi-pulse ultrafast laser ablation |
| topic | Optics Materials Science |
| url | https://arxiv.org/abs/2604.13858 |