Effect of ambient air on femtosecond laser ablation of highly oriented pyrolytic graphite

2014 ◽  
Vol 40 (1) ◽  
pp. 17 ◽  
Author(s):  
Peipei Feng ◽  
Nan Zhang ◽  
Han Wu ◽  
Xiaonong Zhu
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Pyrolytic Graphite ◽  
Femtosecond Laser Ablation ◽  
Ambient Air ◽  
Highly Oriented Pyrolytic Graphite

scholarly journals Study of the formation of 3-D titania nanofibrous structure by MHz femtosecond laser in ambient air

2021 ◽  
Author(s):  
Amirhossein Tavangar ◽  
Bo Tan ◽  
Krishnan Venkatakrishnan
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Deposition Rate ◽  
Femtosecond Laser Ablation ◽  
Ambient Air ◽  
Experimental Results ◽  
Laser Parameters ◽  
Nanofibrous Structure ◽  
Titania Nanostructures ◽  
Multiple Pulses

In this study, we describe the formation mechanism of web-like three-dimensional (3-D) titania nanofibrous structures during femtosecond laser ablation of titanium (Ti) targets in the presence of background air. First, we demonstrate the mechanism of ablation of Ti targets by multiple femtosecond laser pulses at ambient air in an explicit analytical form. The formulas for evaporation rates and the number of ablated particles, which is analogous to the deposition rate of the synthesized nanofibers, for the ablation by a single pulse and multiple pulses as a function of laser parameters, background gas, and material properties are predicted and compared to experimental results. Afterwards, the formation of nanofibrous structures is demonstrated by applying an existing simplified kinetic model to Ti targets and ambient conditions. The predicted theory provides nanofiber diameter dependency with the combination of laser parameters, target properties, and ambient gas characteristics. Experimental studies are then performed on titania nanofibrous structures synthesized by laser ablation of Ti targets using MHz repletion-rate femtosecond laser at ambient air. The models' predictions are then compared with the experimental results, where nanostructures with different morphologies are manufactured by altering laser parameters. Our results indicate that femtosecond laser ablation of Ti targets at air background yields crystalline titania nanostructures. The formation of crystalline titania nanostructures is preceded b thermal mechanism of nucleation and growth. The results point out that laser pulse repetition and dwell time can control the density, size, and pore size of the engineered nanofibrous structure. As the deposition rate of nanostructures is analogous to the ablation rate of the target, higher density of nanofibrous structure is seen at greater laser fluences. The predicted theory can be applied to predict ablation mechanism and nanofiber formation of different materials.

Nanoparticle formation by the debris produced by femtosecond laser ablation of silicon in ambient air

2008 ◽  
Vol 62 (14) ◽  
pp. 2165-2170 ◽  
Author(s):  
N.G. Semaltianos ◽  
W. Perrie ◽  
V. Vishnyakov ◽  
R. Murray ◽  
C.J. Williams ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Femtosecond Laser Ablation ◽  
Ambient Air ◽  
Nanoparticle Formation

scholarly journals Femtosecond laser ablation of brass: A study of surface morphology and ablation rate

2012 ◽  
Vol 30 (3) ◽  
pp. 473-479 ◽  
Author(s):  
Mohamed E. Shaheen ◽  
Brian J. Fryer
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Surface Morphology ◽  
Fine Particles ◽  
Femtosecond Laser Ablation ◽  
Laser Pulses ◽  
Ambient Air ◽  
Ablation Rate ◽  
Femtosecond Laser Pulses ◽  
Nanosecond Laser

AbstractThe interaction of near infrared femtosecond laser pulses with a Cu based alloy (brass) in ambient air at atmospheric pressure and under different laser conditions was investigated. The effects of laser fluence and number of pulses on surface morphology and ablation rate were studied using scanning electron microscopy (SEM) and optical microscopy. Ablation rates were found to rapidly increase from 83 to 604 nm/pulse in the fluence range 1.14–12.21 J/cm2. At fluence >12.21 J/cm2, ablation rates increased slowly to a maximum (607 nm/pulse at 19.14 J/cm2), and then decreased at fluence higher than 20.47 J/cm2 to 564 nm/pulse at 24.89 J/cm2. Large amounts of ablated material in a form of agglomerated fine particles were observed around the ablation craters as the number of laser pulses and fluence increased. The study of surface morphology shows reduced thermal effects with femtosecond laser ablation in comparison to nanosecond laser ablation at low fluence.

Femtosecond laser ablation of polytetrafluoroethylene (Teflon) in ambient air

2003 ◽  
Vol 93 (10) ◽  
pp. 6375-6380 ◽  
Author(s):  
Z. B. Wang ◽  
M. H. Hong ◽  
Y. F. Lu ◽  
D. J. Wu ◽  
B. Lan ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Femtosecond Laser Ablation ◽  
Ambient Air

scholarly journals Femtosecond Laser Nano-Fabrication And Its Biomedical Applications

2021 ◽  
Author(s):  
Amirhossein Tavangar
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Biomedical Application ◽  
Femtosecond Laser Ablation ◽  
Ambient Air ◽  
Femtosecond Laser Pulses ◽  
Device Fabrication ◽  
Ambient Conditions ◽  
Wide Range ◽  
Multiple Pulses

This dissertation aims to develop a new technique for fabrication of three-dimensional (3-D) interwoven nanofibrous platforms using femtosecond laser ablation of solids in ambient conditions. In the first part, the mechanism of ablation of solids by multiple femtosecond laser pulses in ambient air is described in an explicit analytical form. The formulas for evaporation rates and the number of ablated particles for laser ablation by multiple pulses as a function of laser parameters, background gas, and material properties are predicted and compared to experimental results. Later, the formation mechanism of the nanofibrous structures during laser ablation of targets in the presence of air is discussed. The results indicate that femtosecond laser ablation of solids at air background yields crystalline nanostructures. It’s also shown that this technique allows synthesis of 3-D nanostructures on a wide range of materials including synthetic and natural materials. Later, potential practice of the proposed technique for integration of nanostructures on transparent platforms as well as inside microstructures toward device fabrication is investigated. Presented studies show that integrated nanostructure inside microchannels can be fabricated in one single step using this technique. Finally, to address the potential use of the nanostructures for biomedical application, several studies are performed to evaluate the bioactivity and biocompatibility of the nanostructures. The fabricated nanostructures incorporate the functions of 3-D nano-scaled topography and modified chemical properties to improve osseointegration, while at the same time leaving space for delivering other functional agents.

scholarly journals Femtosecond Laser Nano-Fabrication And Its Biomedical Applications

2021 ◽  
Author(s):  
Amirhossein Tavangar
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Biomedical Application ◽  
Femtosecond Laser Ablation ◽  
Ambient Air ◽  
Femtosecond Laser Pulses ◽  
Device Fabrication ◽  
Ambient Conditions ◽  
Wide Range ◽  
Multiple Pulses

This dissertation aims to develop a new technique for fabrication of three-dimensional (3-D) interwoven nanofibrous platforms using femtosecond laser ablation of solids in ambient conditions. In the first part, the mechanism of ablation of solids by multiple femtosecond laser pulses in ambient air is described in an explicit analytical form. The formulas for evaporation rates and the number of ablated particles for laser ablation by multiple pulses as a function of laser parameters, background gas, and material properties are predicted and compared to experimental results. Later, the formation mechanism of the nanofibrous structures during laser ablation of targets in the presence of air is discussed. The results indicate that femtosecond laser ablation of solids at air background yields crystalline nanostructures. It’s also shown that this technique allows synthesis of 3-D nanostructures on a wide range of materials including synthetic and natural materials. Later, potential practice of the proposed technique for integration of nanostructures on transparent platforms as well as inside microstructures toward device fabrication is investigated. Presented studies show that integrated nanostructure inside microchannels can be fabricated in one single step using this technique. Finally, to address the potential use of the nanostructures for biomedical application, several studies are performed to evaluate the bioactivity and biocompatibility of the nanostructures. The fabricated nanostructures incorporate the functions of 3-D nano-scaled topography and modified chemical properties to improve osseointegration, while at the same time leaving space for delivering other functional agents.

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