Femtosecond vs. Picosecond Laser Material Processing

Tuennermann, Andreas; Nolte, Stefan; Limpert, Jens

doi:10.1002/latj.201090006

Cited by 41 publications

(18 citation statements)

References 20 publications

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“…In the current study, the textures processed on Ti6Al4V plates were generated by defining several critical laser parameters: pulse energy, light polarization, spot size on the sample and overlapping of spots on the sample. As it was also reported in others studies,9, 14 the texturing generated by the femtosecond laser was of high quality, which was characterized by a small re‐deposition on the edges of the deposited material and a very small thermally affected zone. In our experiment, only the edges of the 60‐μm microgrooves, with a minor increase in aluminum element, seemed to correspond to a heat‐affected zone.…”

Section: Discussionsupporting

confidence: 78%

Multiscale grooved titanium processed with femtosecond laser influences mesenchymal stem cell morphology, adhesion, and matrix organization

Dumas

Rattner

Vico

et al. 2012

J Biomedical Materials Res

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The femtosecond laser processing enabled the structuring of six types of surfaces on titanium-6aluminium-4vanadium (Ti-6Al-4V) plates. The obtained hierarchical features consisted of a combination of microgrooves and oriented nanostructures. By adjusting beam properties such as laser polarization, the width of the microgrooves (20 or 60 μm) and the orientation of the nanostructures (parallel or perpendicular to the microgrooves) can be precisely controlled. Mesenchymal stem cells (MSCs) grown on these structured surfaces produced cytoplasmic extensions with focal contacts, while on the smooth titanium, the cells were found to be well spread and without any focal contact 12 h postseeding. The 600-nm wide nanostructures on their own were sufficient to orient the MSCs. For the multiscale structured areas, when the orientation of the nanostructures was orthogonal in relation to the microgrooves, there was an important decrease in or even a loss of cell alignment signifying that cells were sensitive to the directional nanostructures in the microgrooves. At 7 days, cell proliferation was not affected but the direction of nanostructures controlled the matrix organization. The ultrafast laser, as a new method for producing micro-nanohybrid surfaces, is a promising approach to promote desired tissue organization for tissue engineering.

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Section: Discussionsupporting

confidence: 78%

Multiscale grooved titanium processed with femtosecond laser influences mesenchymal stem cell morphology, adhesion, and matrix organization

Dumas

Rattner

Vico

et al. 2012

J Biomedical Materials Res

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“…The significance of pulsewidth on the ablation behavior of metals was clearly demonstrated in [2] where the ablation threshold in a Ni film with 0.5-ps UV pulses was 100 times lower than with 14-ns pulses of the same wavelength. The results of [2] and subsequent studies [1,[3][4][5][6][7][8][9][10] led to the generally accepted view that the lowest energy threshold and the best ablation quality are attainable with short (picosecond/femtosecond) pulses; the removal of material starts soon after laser irradiation with a minimal amount of melting. In contrast, with longer pulses, the heating, melting, and vaporization occur during the energy deposition that results in energy losses associated with heat conduction as well as with plasma development above the target [2,5,10,11].…”

Section: Introductionmentioning

confidence: 95%

Drilling rate of five metals with picosecond laser pulses at 355, 532, and 1064 nm

2012

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Experimental results on picosecond laser processing of aluminum, nickel, stainless steel, molybdenum, and tungsten are described. Hole drilling is employed for comparative analysis of processing rates in an air environment. Drilling rates are measured over a wide range of laser fluences (0.05-20 J/cm 2 ). Experiments with picosecond pulses at 355 nm are carried out for all five metals and in addition at 532 nm, and 1064 nm for nickel. A comparison of drilling rate with 6-ps and 6-ns pulses at 355 nm is performed. The dependence of drilling rate on laser fluence measured with picosecond pulses demonstrates two logarithmic regimes for all five metals. To determine the transition from one regime to another, a critical fluence is measured and correlated with the thermal properties of the metals. The logarithmic regime at high-fluence range with UV picosecond pulses is reported for the first time. The energy efficiency of material removal for the different regimes is evaluated. The results demonstrate that UV picosecond pulses can provide comparable quality and higher processing rate compared with literature data on ablation with near-IR femtosecond lasers. A significant contribution of two-photon absorption to the ablation process is suggested to explain high processing rate with powerful UV picosecond pulses.

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“…In practice, pulse energies in the range of 1-100 μJ are appropriate for typical focusing conditions. Scaling the average power by an increased repetition rate at constant pulse energy instead, high scanning speeds are necessary, as the pulse overlap has to be controlled to avoid thermalization of the process, which leads to a reduced ablation quality [4].…”

mentioning

confidence: 99%

Compact diode-pumped 11 kW Yb:YAG Innoslab femtosecond amplifier

et al. 2010

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We demonstrate a compact diode-pumped Yb:KGW femtosecond oscillator-Yb:YAG Innoslab amplifier master oscillator power amplifier (MOPA) with nearly transform-limited 636 fs pulses at 620 W average output power, 20 MHz repetition rate, and beam quality of M(x)(2) = 1.43 and M(y)(2) = 1.35. By cascading two amplifiers, we attain an average output power of 1.1 kW, a peak power of 80 MW, and a 615 fs pulse width in a single linearly polarized beam. The power-scalable MOPA is operated at room temperature, and no chirped-pulse amplification technique is used.

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Femtosecond vs. Picosecond Laser Material Processing

Cited by 41 publications

References 20 publications

Multiscale grooved titanium processed with femtosecond laser influences mesenchymal stem cell morphology, adhesion, and matrix organization

Multiscale grooved titanium processed with femtosecond laser influences mesenchymal stem cell morphology, adhesion, and matrix organization

Drilling rate of five metals with picosecond laser pulses at 355, 532, and 1064 nm

Compact diode-pumped 11 kW Yb:YAG Innoslab femtosecond amplifier

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