Influence of pulse duration in the pico- and femtosecond regime on the absorptance and specific removal rate (Conference Presentation)

Remund, Stefan M.; Chaja, Michalina V.; Zhang, Yiming; Neuenschwander, Beat (2019). Influence of pulse duration in the pico- and femtosecond regime on the absorptance and specific removal rate (Conference Presentation) In: Račiukaitis, Gediminas; Makimura, Tetsuya; Molpeceres, Carlos (eds.) Laser Applications in Microelectronic and Optoelectronic Manufacturing (LAMOM) XXIV (p. 3). SPIE 10.1117/12.2511294

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In ultra-short pulsed laser micromachining of metals shorter pulses generally lead to higher throughput e.g. for copper the specific removal rate drops to about 25 % if the pulse duration is raised from 10 ps to 50 ps and it is increases by about 35 % for a decreased pulse duration of 350 fs. In contrast, a significantly higher increase of 100 % was observed for stainless steel AISI 304 when the pulse duration is decreased from 10 ps to 350 fs, whereas the drop for the longer pulse duration of 50 ps was of the same order of magnitude as for copper. Recent results of a two-pulse burst experiment on copper with temporal varying intra-burst pulse distance have shown, that pulse distances from 10 ps to 100 fs cause only a slight increase in efficiency of approximately 10 % whereas for pulse distances from 10 ps to 500 ps the efficiency is reduced to nearly 50 %. Although, these factors differ from the well-studied pulse duration experiments, they show a similar tendency. Therefore, we assume a dominant common cause. In literature the diminished efficiency is often referred to particle- or plasma shielding for tens of picoseconds pulse durations. In this sense, the ablation of the material during the pulse is faded by itself for longer pulses as well as the ablation of the material from the first pulse is restricted by the second pulse in the burst experiments. Additional investigations concerning reflection and calorimetric considerations will help to underline this hypothesis.

Item Type:	Conference or Workshop Item (Speech)
Division/Institute:	School of Engineering and Computer Science > Institute for Surface Applied Laser, Phototonics and Surface Technologies ALPS School of Engineering and Computer Science
Name:	Remund, Stefan M.; Chaja, Michalina V.; Zhang, Yiming; Neuenschwander, Beat0000-0001-9715-8557; Račiukaitis, Gediminas; Makimura, Tetsuya and Molpeceres, Carlos
Subjects:	Q Science > QC Physics T Technology > TA Engineering (General). Civil engineering (General)
ISBN:	9781510624535
Publisher:	SPIE
Language:	English
Submitter:	Beat Neuenschwander
Date Deposited:	04 Dec 2019 07:46
Last Modified:	04 Nov 2021 21:46
Publisher DOI:	10.1117/12.2511294
Additional Information:	Copyright (2019) Society of Photo‑Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this publication for a fee or for commercial purposes, and modification of the contents of the publication are prohibited
ARBOR DOI:	10.24451/arbor.9344
URI:	https://arbor.bfh.ch/id/eprint/9344