Molecular Dynamics Study of Mechanism of Ablation Induced by a Femtosecond Laser Pulse

2003 ◽  
Author(s):  
Changrui Cheng ◽  
Xianfan Xu
Keyword(s):  
Molecular Dynamics ◽  
Laser Ablation ◽  
Laser Pulse ◽  
Femtosecond Laser ◽  
Critical Point ◽  
Change Process ◽  
Femtosecond Laser Ablation ◽  
Md Simulations ◽  
Femtosecond Laser Irradiation ◽  
Transient Temperature

In this work, molecular dynamics (MD) simulations are carried out to study femtosecond laser ablation of a metal, with an emphasis on the understanding of the mechanism of laser ablation. Theoretically, it has been shown that under intense femtosecond laser irradiation, the material can undergo a volumetric phase change process; its temperature can be close to or even above the critical point. MD simulations allow us to determine the transient temperature of the irradiated material as well as the transient thermodynamic state, which explain the mechanisms of femtosecond laser ablation.

Molecular Dynamics Study of Phase Change Mechanisms During Femtosecond Laser Ablation

2004 ◽  
Vol 126 (5) ◽  
pp. 727-734 ◽  
Author(s):  
Xianfan Xu ◽  
Changrui Cheng ◽  
Ihtesham H. Chowdhury
Keyword(s):  
Molecular Dynamics ◽  
Laser Ablation ◽  
Femtosecond Laser ◽  
Phase Change ◽  
Change Process ◽  
Femtosecond Laser Ablation ◽  
Femtosecond Laser Irradiation ◽  
Maximum Temperature ◽  
Transient Temperature ◽  
Phase Change Process

In this work, Molecular Dynamics (MD) simulation is employed to investigate femtosecond laser ablation of copper, with an emphasis on the understanding of the mechanism of phase change during laser ablation. Laser induced heat transfer, melting, surface evaporation, and material ablation are studied. Theoretically, it has been suggested that under intense femtosecond laser irradiation, the material undergoes a volumetric phase change process; its maximum temperature can be close to or even above the thermodynamic critical point. The MD simulations allow us to determine the transient temperature history of the irradiated material and to reveal the exact phase change process, which explains the mechanisms of femtosecond laser ablation. A finite difference calculation is also performed, which is used to compare results of heating and melting prior to a significant amount of material being ablated.

Non-Equilibrium Thermodynamics and Formation of Nanoparticles in Femtosecond Laser Ablation

2004 ◽  
Author(s):  
Changrui Cheng ◽  
Xianfan Xu
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Femtosecond Laser Ablation ◽  
Md Simulations ◽  
Materials Processing ◽  
High Heating Rate ◽  
Laser Materials ◽  
High Heating ◽  
Temperature And Pressure ◽  
Reduced Temperature

High intensity femtosecond laser ablation processes are computed by molecular dynamics (MD) simulations. The procedure of MD modeling and related numerical techniques are introduced. The volumetric phase separation is illustrated. The emphasis is to understand the thermodynamic state of a material which is heated with an extremely high heating rate, and the formation of particles with nanometer size in the laser-ablated plume. It is revealed that nanoparticles are originated from expansion of a supercritical fluid in a reduced temperature and pressure environment. The parameters of the nanoparticles (temperature, size and velocity) are shown. The results will help to understand femtosecond laser materials processing and applications where nanoparticles are of interest.

Mechanisms of femtosecond laser ablation of Ni3Al: Molecular dynamics study

2021 ◽  
Vol 133 ◽  
pp. 106505
Author(s):  
Zhen Zhang ◽  
Zenan Yang ◽  
Chenchong Wang ◽  
Qiang Zhang ◽  
Shuai Zheng ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Laser Ablation ◽  
Femtosecond Laser ◽  
Femtosecond Laser Ablation

Femtosecond Laser Ablation of Titanium and Silicon

2000 ◽  
Author(s):  
Mengqi Ye ◽  
Costas P. Grigoropoulos
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Laser Fluence ◽  
Laser System ◽  
Femtosecond Laser Ablation ◽  
Laser Pulses ◽  
Femtosecond Laser Irradiation ◽  
Nanosecond Laser ◽  
Iccd Camera ◽  
Plume Emission

Abstract Femtosecond laser ablation of titanium and silicon samples has been studied via time-of-flight (TOF), emission spectroscopy and microscopy measurement. Laser pulses of around 100 fs (FWHM) at λ = 800 nm were delivered by a Ti:sapphire femtosecond laser system. A vacuum chamber with a base pressure of 10−7 torr was built for ion TOF measurement. These ion TOF spectra were utilized to determine the velocity distribution of the ejected ions. While nanosecond laser ablation typically generates ions of a few tens of eV, femtosecond laser irradiation even at moderate energy densities can produce energetic ions with energies of up to a few keV. The most probable energy of these fast ions is proportional to the laser fluence. The structure and number of peaks of the TOF spectra varies with the laser fluence. Images of plume emission were captured by an intensified CCD (ICCD) camera. The plume emission spectrum was analyzed by a spectrometer. Laser ablated craters were measured by an interferometric microscope and a scanning electron microscope (SEM). Ablation yield was expressed as a function of laser fluence, and number of shots.

Femtosecond laser ablation of polystyrene: A molecular dynamics study

2015 ◽  
Vol 132 (43) ◽  
pp. n/a-n/a
Author(s):  
Yanhua Huang ◽  
Chengwei Song ◽  
Junjie Zhang ◽  
Tao Sun
Keyword(s):  
Molecular Dynamics ◽  
Laser Ablation ◽  
Femtosecond Laser ◽  
Femtosecond Laser Ablation
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