Time-resolved shadowgraphic study of femtosecond laser ablation of aluminum under different ambient air pressures

2011 ◽  
Vol 109 (5) ◽  
pp. 053113 ◽  
Author(s):  
Yasuaki Okano ◽  
Yoichiro Hironaka ◽  
Ken-ichi Kondo ◽  
Kazutaka G. Nakamura

2021 ◽  
Author(s):  
Amirhossein Tavangar ◽  
Bo Tan ◽  
Krishnan Venkatakrishnan

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.


2012 ◽  
Vol 108 (2) ◽  
pp. 343-349 ◽  
Author(s):  
Aivaras Urniežius ◽  
Nerijus Šiaulys ◽  
Viačeslav Kudriašov ◽  
Valdas Sirutkaitis ◽  
Andrius Melninkaitis

1998 ◽  
Vol 127-129 ◽  
pp. 76-80 ◽  
Author(s):  
A Rosenfeld ◽  
D Ashkenasi ◽  
H Varel ◽  
M Wähmer ◽  
E.E.B Campbell

2012 ◽  
Vol 20 (28) ◽  
pp. 29329 ◽  
Author(s):  
Takuro Tomita ◽  
Minoru Yamamoto ◽  
Noboru Hasegawa ◽  
Kota Terakawa ◽  
Yasuo Minami ◽  
...  

2008 ◽  
Vol 62 (14) ◽  
pp. 2165-2170 ◽  
Author(s):  
N.G. Semaltianos ◽  
W. Perrie ◽  
V. Vishnyakov ◽  
R. Murray ◽  
C.J. Williams ◽  
...  

1999 ◽  
Vol 103 (51) ◽  
pp. 11257-11263 ◽  
Author(s):  
Koji Hatanaka ◽  
Tamitake Itoh ◽  
Tsuyoshi Asahi ◽  
Nobuyuki Ichinose ◽  
Shunichi Kawanishi ◽  
...  

2012 ◽  
Vol 30 (3) ◽  
pp. 473-479 ◽  
Author(s):  
Mohamed E. Shaheen ◽  
Brian J. Fryer

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.


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