Thermal effects in femtosecond laser ablation of metals

Chen, Guo

doi:10.1117/12.641332

Cited by 7 publications

(3 citation statements)

References 41 publications

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“…When a single laser pulse interacted with the aluminum surface, laser energy was absorbed on the surface. At that time, thermal effects on the laser-treated area occurred [37][38][39]. The estimated maximum temperature was about 546 • C, as calculated by thermal models [38,40].…”

Section: Mechanism Of Wettability Conversion With Single-shot Nanosec...mentioning

confidence: 88%

Scalable Wettability Modification of Aluminum Surface through Single-Shot Nanosecond Laser Processing

Ngo

Liu

et al. 2023

Nanomaterials

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Conversion of a regular metal surface to a superhydrophobic one has great appeal because of the wide range of potential applications such as anti-fouling, anti-corrosion, and anti-icing. One promising technique is to modify surface wettability by laser processing to form nano-micro hierarchical structures with various patterns, such as pillars, grooves, and grids, followed by an aging process in the air or additional chemical processes. Surface processing is typically a lengthy process. Herein, we demonstrate a facile laser technique that converts the surface wettability of aluminum from inherently hydrophilic to hydrophobic and superhydrophobic with single-shot nanosecond laser irradiation. A single shot covers a fabrication area of approximately 19.6 mm2. The resultant hydrophobic and superhydrophobic effects persisted after six months. The effect of the incident laser energy on the surface wettability is studied, and the underlying mechanism of the wettability conversion through single-shot irradiation is suggested. The obtained surface shows a self-cleaning effect and the control of water adhesion. The single-shot nanosecond laser processing technique promises a fast and scalable method to produce laser-induced surface superhydrophobicity.

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Section: Mechanism Of Wettability Conversion With Single-shot Nanosec...mentioning

confidence: 88%

Scalable Wettability Modification of Aluminum Surface through Single-Shot Nanosecond Laser Processing

Ngo

Liu

et al. 2023

Nanomaterials

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“…In nanosecond laser ablation (the pulse duration is less than 10 À6 s) a large heat-affected zone exceeding 20 mm can be created in metallic materials [1]. The use of a femtosecond laser (pulse duration < 10 12 s) reduces the amount of energy transported into the area around the ablation zone; however, there is still sufficient energy to create a heat-affected zone (albeit smaller than in the nanosecond case) and redeposition of the target material [2][3][4][5][6][7]. In theory, only when the pulse duration is shorter than the electron cooling time of the ablated material can non-thermal ablation be achieved.…”

Section: Introductionmentioning

confidence: 99%

High-precision fabrication of Pd film by laser rear-side ablation with thick sacrificial layer

Wang

Jiang

et al. 2011

Proceedings of the Institution of Mechanical Engineers, Part B:

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Thermal damage can be a major problem in laser machining thin films. This paper proposes a laser rear-side ablation technique that incorporates a sacrificial layer to absorb excess energy, thereby lessening the level of thermal damage created in the laser processing of metallic films. The sacrificial layer is placed between the quartz substrate and the metallic film. Experiments were performed on the laser machining of holes in a palladium film using phenol formaldehyde resin as the sacrificial layer in which the pulse energy and sacrificial layer thickness were varied. The experimental results validate the proposed approach in that the judicious choice of the values of the pulse energy and the thickness of the sacrificial layer lead to the creation of high-quality holes that do not display the effects of thermal damage. Thus, the proposed technique can be considered to be a promising method for the laser machining of metal films.

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“…For our case, since increasing melting and solidification is observed with increase cumulative fluence base on the SEM results, it is also presumed that the remaining laser energy did not further contribute to the ablation process. This excess or residual laser energy induced heat and formed a very thin layer of melt around the laser ablated crater (Hirayama and Obara, 2002;Guo, 2006). It is reasonable to assume that femtosecond laser ablation often involves fast heating and cooling due to the very short pulse duration.…”

Section: Tem Analysis Of Fs Laser Irradiated Titaniummentioning

confidence: 99%

Femtosecond laser interaction with fused silica in surface structuring

Tan¹

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The need for miniaturisation in devices in today's industries has led to a vast array of micromachining processes. Yet, micromachining of glass remains a great challenge due to the extreme brittleness and hardness of the material. With the development of the chirped pulse amplification (CPA) technique in the mid-1980s, powerful femtosecond (10-15 s) laser systems are now readily available in the market for carrying out micromachining on various materials. Femtosecond (fs) lasers have several advantages over their long pulse laser counterparts. First, the high intensity of femtosecond laser pulse will easily triggers the multiphoton absorption process to occur in transparent material enabling bulk modification within the transparent materials. Moreover, the ultrashort pulse duration (~100 fs) of a femtosecond laser enables energy to be dissipated before thermal diffusion occurs (~10 ps), thus collateral damages around the machined area is minimized. These unique properties have opened up new opportunities in using femtosecond lasers for carrying out micromachining and micro fabrication of glass and other transparent materials. Despite the ongoing work to study femtosecond laser-material interaction, practical use of femtosecond laser for industrial application can be still considered at the development stage as the beam interaction process is not well understood. New physical mechanism and phenomenon can arise when the machining is performed using different materials and conditions. Therefore, in this research, a femtosecond laser was used to carry ablation of transparent material in air using fused silica as a model optical material. The objective of this research is to gain a better understanding on the femtosecond laser irradiation effects on fused silica so that it can be applied to practical micromachining processes. These effects include ripple formation, change in crystal structures and surface morphologies as well as how the laser irradiated Abstract ii machined profiles respond to various laser parameters. Special attention was paid to characterize the laser irradiated morphologies and structures as well as studying phenomenon related to micromachining of fused silica. Major results and new findings are summarized as follows: Femtosecond laser induced periodic structures on fused silica were systematically studied by irradiating the surface using a wide range of laser processing parameters. It is found that two directional ripples having periods smaller than the laser wavelength can be formed on the surface of fused silica. It is demonstrated that the the origin of the coarse ripple is related to the ultrafast melting and solidification of fused silica and the fine ripple is a result of harmonica wave generation. It is also found that orientation and period of these ripple structures can be controlled experimentally by varying the beam polarization. It is further observed that the influence of the surface defect like scratches exert an even stronger influence on the ripple orientation than the beam polari...

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Thermal effects in femtosecond laser ablation of metals

Cited by 7 publications

References 41 publications

Scalable Wettability Modification of Aluminum Surface through Single-Shot Nanosecond Laser Processing

Scalable Wettability Modification of Aluminum Surface through Single-Shot Nanosecond Laser Processing

High-precision fabrication of Pd film by laser rear-side ablation with thick sacrificial layer

Femtosecond laser interaction with fused silica in surface structuring

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