Modeling of multi-burst mode pico-second laser ablation for improved material removal rate

Wei, Hu; Shin, Yung C.; King, Galen B.

doi:10.1007/s00339-009-5405-x

Cited by 99 publications

(48 citation statements)

References 23 publications

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“…Closely grouped pulses with pulse to pulse separation in the order of a few nanoseconds have a potential for increasing material removal rates [2] and thereby reducing the thermal effects. Besides, keeping the burst repetition period in the order of thermal relaxation time has the advantage of keeping the overall average power at lower levels in order to prevent the cumulative heating of the material.…”

mentioning

confidence: 99%

Non-thermal material and tissue processing with 100 MHz and 500 MHz repetition rate bursts

Kerse

Kalaycıoğlu

Akaalan

et al. 2013

2013 Conference on Lasers &Amp; Electro-Optics Europe &Amp; International Quantum Electronics Conference CLEO EUROPE/IQEC

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There are a number of applications that would avail a pulse pattern in the form of closely grouped and uniformly spaced pulses, i.e., bursts [1]. Closely grouped pulses with pulse to pulse separation in the order of a few nanoseconds have a potential for increasing material removal rates [2] and thereby reducing the thermal effects. Besides, keeping the burst repetition period in the order of thermal relaxation time has the advantage of keeping the overall average power at lower levels in order to prevent the cumulative heating of the material.Here, we demonstrate results on ablation efficiency for three different pulse repetition rates for Cu targets and results on human dentine samples to emphasize the detrimental thermal effects for low repetition rate mode. We used custom built Yb fiber amplifier, which produces bursts at an overall repetition rate up to 1 kHz comprising of 25 pulses each with up to tens of μJs of energy, ∼1ps pulse duration and intra-burst repetition rate of 100 MHz and 500 MHz ( Fig. 1(a)). The system can also produce pulses with 25 kHz uniform repetition rate (not bursts), which we used it for our low repetition rate mode. We kept the individual pulse energy, average power, pulse width, spot size and total number of incident pulses (hence total processing time) strictly constant. Fig. 1(b) shows results obtained on a 100 μm thick Cu targets in ambient atmosphere at room temperature using the three modes of operations, where we have characterized the depth of ablation per pulse. Fig. 1(c) shows results obtained on human dentine, where areas of 1 mm 2 in each sample were raster scanned with scan velocity of 0.1 mm/s. Comparison of material ablation rate per pulse for copper target using 25 pulses at repetition rates of 25 kHz, 100 MHz, and 500 MHz; showing that ablation per pulse increases by ∼6 times at higher repetition rates. (c) Human dentine samples processed using uniform repetition rate of 25 kHz (i), and 25-pulse bursts at 1-kHz burst repetition rate with 100-MHz intra-burst (ii) and 500-MHz intra-burst (iii) repetition rate. Average power, processing time, pulse width, pulse energy, spot size are the same in each case.In conclusion, we have developed a mJ-level burst-mode integrated fiber amplifier with high in-burst repetition rates, and compressed pulses of ∼1 ps. Our micromachining results demonstrate almost an order of magnitude increase in volume of ablated material per pulse at higher repetition rates, along with much reduced thermal effects. References

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mentioning

confidence: 99%

Non-thermal material and tissue processing with 100 MHz and 500 MHz repetition rate bursts

Kerse

Kalaycıoğlu

Akaalan

et al. 2013

2013 Conference on Lasers &Amp; Electro-Optics Europe &Amp; International Quantum Electronics Conference CLEO EUROPE/IQEC

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“…The TTM describes the evolution of the temperature increase due to the absorption of a laser pulse within the solid and is applied to model physical phenomena like the energy transfer between electrons and lattice occurring during the target-laser interaction [15]. Onedimension two-temperature equation is given below [16,17]:…”

Section: Mathematical Modelmentioning

confidence: 99%

Thermal behavior of thin metal films irradiated by shaped femtosecond pulse sequences laser

Chen¹,

Jiang²,

Sui³

et al. 2011

Optics Communications

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“…Initially, burst-mode processing was promoted by commercial companies for high-average power picosecond lasers [8][9][10] to reach higher level of machining quality and productivity. In experimental studies, it is demonstrated, therefore, that the ablation rate increases substantially if operating picosecond lasers in burst-mode regime and 20-ns inter-pulse delay instead of irradiating high-energy pulses at similar average laser power [11][12][13][14]. For bursts with shorter inter-pulse delay, it was reported that plasma shielding limits the removal efficiency [14] while longer delays cause highenergy plasma generation that is explosively remelting the surface, in turn increasing surface roughness significantly [11].…”

Section: Introductionmentioning

confidence: 96%

Experimental study on double-pulse laser ablation of steel upon multiple parallel-polarized ultrashort-pulse irradiations

et al. 2016

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In this paper, double-pulse laser processing is experimentally studied with the aim to explore the influence of ultrashort pulses with very short time intervals on ablation efficiency and quality. For this, sequences of 50 double pulses of varied energy and inter-pulse delay, as adjusted between 400 fs and 18 ns by splitting the laser beam into two optical paths of different length, were irradiated to technical-grade stainless steel. The depth and the volume of the craters produced were measured in order to evaluate the efficiency of the ablation process; the crater quality was analyzed by SEM micrographs. The results obtained were compared with craters produced with sequences of 50 single pulses and energies equal to the double pulse. It is demonstrated that double-pulse processing cannot exceed the ablation efficiency of single pulses of optimal fluence, but the ablation crater surface formed smoother if inter-pulse delay was in the range between 10 ns and 18 ns. In addition, the influence of pulse duration and energy distribution between the individual pulses of the double pulse on ablation was studied. For very short inter-pulse delay, no significant effect of energy variation within the double pulse on removal rate was found, indicating that the double pulse acts as a big single pulse of equal energy. Further, the higher removal efficiency was achieved when double-pulse processing using femtosecond pulses instead of picosecond pulses.

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Modeling of multi-burst mode pico-second laser ablation for improved material removal rate

Cited by 99 publications

References 23 publications

Non-thermal material and tissue processing with 100 MHz and 500 MHz repetition rate bursts

Non-thermal material and tissue processing with 100 MHz and 500 MHz repetition rate bursts

Thermal behavior of thin metal films irradiated by shaped femtosecond pulse sequences laser

Experimental study on double-pulse laser ablation of steel upon multiple parallel-polarized ultrashort-pulse irradiations

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