Theoretical determination of the ablation rate of metals in multiple-nanosecond laser pulses irradiation regime

2007 ◽  
Vol 253 (15) ◽  
pp. 6353-6358 ◽  
Author(s):  
Mihai Stafe ◽  
Constantin Negutu ◽  
Ion M. Popescu
Keyword(s):  
Laser Pulses ◽  
Ablation Rate ◽  
Nanosecond Laser ◽  
Theoretical Determination ◽  
Irradiation Regime ◽  
Nanosecond Laser Pulses

Impact of the lasr wavelength and fluence on the ablation rate of aluminium

Open Physics ◽  
2008 ◽  
Vol 6 (2) ◽  
Author(s):  
Mihai Stafe ◽  
Ionut Vladoiu ◽  
Ion Popescu
Keyword(s):  
Plasma Plume ◽  
Second Harmonic ◽  
Laser System ◽  
Target Surface ◽  
Threshold Value ◽  
Laser Pulses ◽  
Ablation Rate ◽  
Nanosecond Laser ◽  
Nanosecond Laser Pulses ◽  
532 Nm

AbstractThe dependence of the ablation rate of aluminium on the fluence of nanosecond laser pulses with wavelengths of 532 nm and respectively 1064 nm is investigated in atmospheric air. The fluence of the pulses is varied by changing the diameter of the irradiated area at the target surface, and the wavelength is varied by using the fundamental and the second harmonic of a Q-switched Nd-YAG laser system. The results indicate an approximately logarithmic increase of the ablation rate with the fluence for ablation rates smaller than ∼6 μm/pulse at 532 nm, and 0.3 μm/pulse at 1064 nm wavelength. The significantly smaller ablation rate at 1064 nm is due to the small optical absorptivity, the strong oxidation of the aluminium target, and to the strong attenuation of the pulses into the plasma plume at this wavelength. A jump of the ablation rate is observed at the fluence threshold value, which is ∼50 J/cm2 for the second harmonic, and ∼15 J/cm2 for the fundamental pulses. Further increasing the fluence leads to a steep increase of the ablation rate at both wavelengths, the increase of the ablation rate being approximately exponential in the case of visible pulses. The jump of the ablation rate at the threshold fluence value is due to the transition from a normal vaporization regime to a phase explosion regime, and to the change of the dimensionality of the hydrodynamics of the plasma-plume.

Formation of Periodical Sub-Micron Sized Structures on Silicon by Interfered Nanosecond Laser Pulses

2010 ◽  
Vol 97-101 ◽  
pp. 3803-3806
Author(s):  
Yong Xiang Hu ◽  
Heng Zhang ◽  
Zheng Qiang Yao
Keyword(s):  
Cost Effective ◽  
Laser Pulses ◽  
Laser Beams ◽  
Nanosecond Laser ◽  
Effective Technique ◽  
First Order ◽  
Direct Fabrication ◽  
Cost Effective Technique ◽  
Nanosecond Laser Pulses ◽  
Micro Structuring

Laser interference micro-structuring is a relatively efficient and cost-effective technique for fabricating periodical micro-nano-structuring surfaces. The direct fabrication of sub-micron sized dot array on silicon was performed by four interfering nanosecond laser beams with a diffractive beam splitter. The mechanism to form the dot array was analyzed and it was found that the obtained conical dot array had a negative shape of the interference pattern of four laser beams. A second-order peak between two first-order peaks also occurred due to the liquid-solid expansion.

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