scholarly journals Process limits for percussion drilling of stainless steel with ultrashort laser pulses at high average powers

2021 ◽  
Vol 128 (1) ◽  
Author(s):  
David Brinkmeier ◽  
Daniel Holder ◽  
André Loescher ◽  
Christoph Röcker ◽  
Daniel J. Förster ◽  
...  
Keyword(s):  
Ultrafast Lasers ◽  
Power Level ◽  
Average Power ◽  
High Volume ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Ambient Atmosphere ◽  
Heat Accumulation ◽  
Manufacturing Applications ◽  
Percussion Drilling

AbstractThe availability of commercial ultrafast lasers reaching into the kW power level offers promising potential for high-volume manufacturing applications. Exploiting the available average power is challenging due to process limits imposed by particle shielding, ambient atmosphere breakdown, and heat accumulation effects. We experimentally confirm the validity of a simple thermal model, which can be used for the estimation of a critical heat accumulation threshold for percussion drilling of AISI 304 steel. The limits are summarized in a processing map, which provides selection criteria for process parameters and suitable lasers. The results emphasize the need for process parallelization.

scholarly journals Analytical model for the depth progress of percussion drilling with ultrashort laser pulses

2021 ◽  
Vol 127 (5) ◽  
Author(s):  
Daniel Holder ◽  
Rudolf Weber ◽  
Thomas Graf ◽  
Volkher Onuseit ◽  
David Brinkmeier ◽  
...  
Keyword(s):  
Analytical Model ◽  
Experimental Validation ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Picosecond Pulses ◽  
Hole Depth ◽  
Laser Percussion Drilling ◽  
Pulse Energies ◽  
Ultrashort Laser ◽  
Percussion Drilling

AbstractA simplified analytical model is presented that predicts the depth progress during and the final hole depth obtained by laser percussion drilling in metals with ultrashort laser pulses. The model is based on the assumption that drilled microholes exhibit a conical shape and that the absorbed fluence linearly increases with the depth of the hole. The depth progress is calculated recursively based on the depth changes induced by the successive pulses. The experimental validation confirms the model and its assumptions for percussion drilling in stainless steel with picosecond pulses and different pulse energies.

scholarly journals High-quality percussion drilling with ultrashort laser pulses

2021 ◽  
Vol 127 (9) ◽  
Author(s):  
A. Feuer ◽  
R. Weber ◽  
R. Feuer ◽  
D. Brinkmeier ◽  
T. Graf
Keyword(s):  
Stainless Steel ◽  
Laser Fluence ◽  
Ablation Threshold ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
High Quality ◽  
Edge Quality ◽  
Ultrashort Laser ◽  
Percussion Drilling

AbstractThe influence of the laser fluence on the quality of percussion-drilled holes was investigated both experimentally and by an analytical model. The study reveals that the edge quality of the drilled microholes depends on the laser fluence reaching the rear exit of the hole and changes with the number of pulses applied after breakthrough. The minimum fluence that must reach the hole’s exit in order to obtain high-quality microholes in stainless steel was experimentally found to be 2.8 times the ablation threshold.

scholarly journals The challenges of productive materials processing with ultrafast lasers

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Rudolf Weber ◽  
Thomas Graf
Keyword(s):  
Ultrafast Lasers ◽  
Average Power ◽  
Processing System ◽  
Processing Parameters ◽  
Materials Processing ◽  
High Tech ◽  
X Rays ◽  
Heat Accumulation ◽  
Physical Limitations ◽  
Air Breakdown

Abstract Materials processing with ultrafast lasers with pulse durations in the range between about 100 fs and 10 ps enable very promising and emerging high-tech applications. Moreover, the average power of such lasers is steadily increasing; multi kilowatt systems have been demonstrated in laboratories and will be ready for the market in the next few years, allowing a significantly increase in productivity. However, the implementation of ultrafast laser processes in applications is very challenging due to fundamental physical limitations. In this paper, the main limitations will be discussed. These include limitations resulting from the physical material properties such as the ablation depth and the optimal fluence, from processing parameters such as air-breakdown and heat accumulation, from the processing system such as thermal focus shift, and from legal regulations due to the potential emission of soft X-rays.

scholarly journals Ultrafast lasers and their applications

2016 ◽  
Vol 8 (4) ◽  
pp. 94
Author(s):  
Jaroslaw Sotor ◽  
Grzegorz Sobon
Keyword(s):  
Ultrafast Lasers ◽  
Laser Pulses ◽  
Laser Micromachining ◽  
Supercontinuum Generation ◽  
Ultrashort Laser Pulses ◽  
Main Topic ◽  
Special Issue ◽  
Practical Applications ◽  
Saturable Absorbers ◽  
Ultrashort Laser

The editors introduce the special issue on "Ultrafast lasers and their applications". It covers topics from ultrashort laser pulses generation using nanomaterials-based saturable absorbers to practical applications of such lasers in spectroscopy, supercontinuum generation and laser micromachining. The issue contains nine papers tightly focused on the main topic and two regular papers.

scholarly journals Improved stability of a compact vacuum-free laser-plasma X-ray source

2020 ◽  
Vol 8 ◽  
Author(s):  
L. Martín ◽  
J. Benlliure ◽  
D. Cortina-Gil ◽  
J. Peñas ◽  
C. Ruiz
Keyword(s):  
Laser Plasma ◽  
Average Power ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Target System ◽  
Average Dose ◽  
X Ray ◽  
Positioning Errors ◽  
Improved Stability ◽  
Ultrashort Laser

We report the development of a stable high-average power X-ray source generated by the interaction of ultrashort laser pulses (35 fs, 1 mJ, 1 kHz) with a solid target in air. The achieved source stability, which is essential for the applications foreseen for these laser-driven plasma accelerators, is due to the combination of precise positioning of the target on focus and the development of a fast rotating target system able to ensure the refreshment of the material at every shot while minimizing positioning errors with respect to the focal spot. This vacuum-free laser-plasma X-ray source provides an average dose rate of 1.5 Sv/h at 30 cm and a repeatability better than 93% during more than 36 min of continuous operation per target.

Investigation of the ejected mass during high-intensity laser solid interaction for improved plasma mirror generation

2022 ◽  
Author(s):  
Gregor F. H. Indorf ◽  
Graeme G Scott ◽  
Malte A. Ennen ◽  
Pierre Forestier-Colleoni ◽  
David Haddock ◽  
...  
Keyword(s):  
High Intensity ◽  
Contrast Ratio ◽  
Average Power ◽  
Laser Pulses ◽  
High Repetition Rate ◽  
Ultrashort Laser Pulses ◽  
Intense Laser ◽  
High Intensity Laser ◽  
Laser Systems ◽  
Intensity Laser

Abstract The interaction of very intense and ultrashort laser pulses with solid targets is a topic that has attracted a large amount of interest in science and applications. This interest is boosted by the large progress made in the development of high repetition rate, high-power laser systems. With the significant increase in average power, there is concern about how to deal with ablated debris that may lead to contamination and damage during interaction experiments with solid targets. This issue is also highly relevant in experiments that include plasma mirrors. These are often employed to increase the contrast ratio of the intense laser pulse to unwanted laser pre-pulses from the amplifier chain and/or the background of amplified spontaneous emission. For this reason, the present work investigates the mass ejected from the target into vacuum for different conditions, particularly those present when plasma mirrors are introduced. The total amount of ablated mass can be reduced by making use of a temporally controlled plasma expansion that enhances the plasma mirror reflectivity. In this way, high intensity laser interaction experiments can be carried out with efficient and clean plasma mirrors significantly reducing the degradation of the laser optics and plasma diagnostics placed near the interaction.

Femtosecond Laser Pulses Operation in Crystal under High-Power Diode Pumping

2015 ◽  
Vol 1101 ◽  
pp. 169-172
Author(s):  
Brij Mohan Kumar Prasad ◽  
Amrit Bawankan
Keyword(s):  
Beam Quality ◽  
Average Power ◽  
Visible Region ◽  
Laser Pulses ◽  
Mode Locking ◽  
Femtosecond Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Semiconductor Saturable Absorber ◽  
Bonding Failure ◽  
Ultrashort Laser

We report on a diode laser which is used to pump directly the crystal with a semiconductor saturable absorber allows passive mode locking for the generation of pulses with an average power along with the broadband light by focusing on ultrashort laser pulses into crystal tungstate. The nonuniformity can lead to the crystal and bonding failure. Also model the thermal and structural properties at the various tempeartures to observe the beam quality. Extends the generated spectrum from the infrared to ultraviolet through the visible region, it consists of discrete spatially separated sidebands.

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