The role of plasma in ablation of materials by ultrashort laser pulses

Klimentov, S. M.; Kononenko, T. V.; Pivovarov, P. A.; Garnov, S. V.; Konov, V. I.; Prokhorov, A. M.; Breitling, Detlef; Dausinger, Friedrich

doi:10.1070/qe2001v031n05abeh001958

Cited by 58 publications

(19 citation statements)

References 2 publications

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“…Later, we will propose an explanation for the observed contrast between picosecond and femtosecond time domains, when additional experimental data is drilling achieves the maximum and nearly constant value at the pressure below 100÷300 mbar. plasma was shown to dominate in the picosecond pulsewidth range [5]. This phenomenon manifests itself as a dependence of the air breakdown threshold on laser irradiation prehistory.…”

Section: Resultsmentioning

confidence: 93%

“…Using optical transmission methods, the energy thresholds of the breakdown ignited by these particles were measured to be 20÷30 J/cm2 in steel channels and 6O--8O J/cm2 j channels of the ceramics of Si3N4 drilled by 300 ps pulses of Nd:YAP laser [5]. For comparison, the breakdown threshold for pure air in this pulse-width range exceeds 150 J/cm2, while the surface plasma formation occurs at -0.5 J/cm2.…”

Section: Resultsmentioning

confidence: 99%

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Role of gas environment in the process of deep-hole drilling by ultrashort laser pulses

et al. 2003

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Fax: (0711) 6856842The detailed study of the role of air pressure in deep hole drilling by femtosecond and picosecond intense laser pulses (Ti:A1203 and Nd:YAP lasers) was performed in the range 1÷1000 mBar. Steel sample plates were mostly tested, experimental data obtained for ceramic materials is also presented. The following ablation parameters were measured and analyzed: ablation rates and their dependence on the channel depth, ablated crater morphology, optical transmission in channels after through hole formation. Both percussion and helical drilling regimes were used.Special attention was paid to two strong gas assisted effects typical of sub-picosecond and subnanosecond material ablation, which are low threshold gas breakdown in deep channels and nonlinear interaction of ultra-short intense pulses with air resulting in conical emission. Unwanted aspects of both phenomena were shown to disappear in a moderate vacuum of lOO mBar. A new approach to formation of such a vacuum in drilled channels was also proposed and experimentally modeled using ultra-high repetition rate nanosecond laser pulses.Keywords: laser ablation in air and vacuum, ultra-short pulses, deep channels, air breakdown, white light continuum generation, ultra-high repetition rate laser exposure

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Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Role of gas environment in the process of deep-hole drilling by ultrashort laser pulses

et al. 2003

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“…Instead, for this case the achievable hole depth is slightly lower than the one predicted by the model. This is mainly due to a particle-ignited plasma, which can occur at high fluences for pulse durations of several picoseconds [24,25]. The final area within such a hole then is larger than the one of a pure conical hole due to the formed bulge in the middle of the hole.…”

Section: Experimental Verificationmentioning

confidence: 99%

Estimation of the depth limit for percussion drilling with picosecond laser pulses

Förster¹,

Weber²,

Holder³

et al. 2018

Opt. Express

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We present a model to predict the final depth of percussion-drilled holes that are produced with picosecond laser pulses in metals. It is based on the assumption that boreholes always have conical geometries when the drilling process terminates. We show that the model is valid for various process parameters when drilling in stainless steel. This was even confirmed by drilling with 3 mJ pulses, which resulted in a 10 mm deep borehole without thermal damage.

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“…The reduction of the HAZ leads to much sharper contours of the laser-processed structures compared to the nanosecond ablation case and, as a consequence, to much better quality of surface processing [1,2]. Generally, the femtosecond laser-based micromachining is performed at relatively low laser fluences and under reduced ambient pressures (in vacuum) to exclude or minimize the impact of plasma effects that can lead to undesirable secondary treatment of the target and consequent deterioration of the processing quality [3,4].…”

Section: Introductionmentioning

confidence: 99%

Surface modifications during femtosecond laser ablation in vacuum, air, and water

Besner

Degorce

Kabashin

et al. 2004

Photonics North 2004: Photonic Applications in Astronomy, Biomedicine, Imaging, Materials Processing, and Education

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Femtosecond laser ablation technique has been used to process Si and Au targets in vacuum, air and water environment. The threshold of ablation was found to be much lower for Si compared to Au and that was related to much better radiation absorption of Si. The values of the threshold were almost identical for vacuum, air and water in the case of Si (0.4 J/cm 2 0.2 J/cm 2 in the single and multi-pulse irradiation regime, respectively) and Au (0.9 J/cm 2 and 0.3 J/cm 2 ). Craters on the surface of Si and Au were essentially similar for low fluences, suggesting an involvement of the same radiation-related mechanism of material removal, whereas for high fluences significant differences could take place. In particular, quite different crater morphologies were observed during the laser ablation in water, including ones with nanoporous layers for Si and ones with concentric spheres for Au. The differences of morphologies for high laser fluences were explained by the involvement of plasma-related effects under the processing in relatively dense media.

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The role of plasma in ablation of materials by ultrashort laser pulses

Cited by 58 publications

References 2 publications

Role of gas environment in the process of deep-hole drilling by ultrashort laser pulses

Role of gas environment in the process of deep-hole drilling by ultrashort laser pulses

Estimation of the depth limit for percussion drilling with picosecond laser pulses

Surface modifications during femtosecond laser ablation in vacuum, air, and water

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