Materials Removals During Femtosecond Laser Non-Thermal Ablation of Dielectrics

2006 ◽  
Author(s):  
Lan Jiang ◽  
Hai-Lung Tsai
Keyword(s):  
Experimental Data ◽  
Laser Ablation ◽  
Femtosecond Laser ◽  
Electron Density ◽  
Free Electron ◽  
Femtosecond Laser Ablation ◽  
Threshold Fluence ◽  
Plasma Model ◽  
Free Electron Density ◽  
Two Temperature

It remains a big challenge to theoretically predict the material removals mechanism in femtosecond laser ablation. To bypass this unresolved problem, many calculations of femtosecond laser ablation of non-metals have been based on free electron density distribution without the actual consideration of the phase change mechanism. However, this widely-used key assumption needs further theoretical and experimental confirmations. By combining the plasma model and improved two-temperature model developed by the authors, this study focuses on investigating ablation threshold fluence, depth, and shape during femtosecond laser ablation of dielectrics through non-thermal processes (the Coulomb explosion and electrostatic ablation). The predicted ablation depths and shapes in fused silica, by using 1) the plasma model only and 2) the plasma model plus the two-temperature equation, are both in agreement with published experimental data. The widely-used assumptions for threshold fluence, ablation depth, and shape in the plasma model based on free electron density are validated by the comparison study and experimental data.

Femtosecond laser high-efficiency drilling of high-aspect-ratio microholes based on free-electron-density adjustments

2014 ◽  
Vol 53 (31) ◽  
pp. 7290 ◽  
Author(s):  
Lan Jiang ◽  
Juqiang Fang ◽  
Qiang Cao ◽  
Kaihu Zhang ◽  
Peng Wang ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Femtosecond Laser ◽  
Electron Density ◽  
High Aspect Ratio ◽  
Free Electron ◽  
High Efficiency ◽  
Free Electron Density

scholarly journals Simulation of laser ablation of metals for nanoparticles production

2016 ◽  
Vol 41 ◽  
pp. 1660143 ◽  
Author(s):  
R. V. Davydov ◽  
V. I. Antonov ◽  
T. I. Davydova
Keyword(s):  
Experimental Data ◽  
Laser Ablation ◽  
Femtosecond Laser Ablation ◽  
Hydrodynamic Equations ◽  
Temperature Model ◽  
Wide Range ◽  
Simulation Results ◽  
Range Equation ◽  
Two Temperature ◽  
Good Agreement

In this paper a mathematical model for femtosecond laser ablation of metals is proposed, based on standard two-temperature model connected with 1D hydrodynamic equations. Wide-range equation of state has been developed. The simulation results are compared with experimental data for aluminium and copper. A good agreement for both metals with numerical results and experiment shows that this model can be employed for choosing laser parameters to better accuracy in nanoparticles production by ablation of metals.

scholarly journals Improved two-temperature model and its application in femtosecond laser ablation of metal target

2010 ◽  
Vol 28 (1) ◽  
pp. 157-164 ◽  
Author(s):  
Ranran Fang ◽  
Duanming Zhang ◽  
Hua Wei ◽  
Zhihua Li ◽  
Fengxia Yang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Laser Ablation ◽  
Femtosecond Laser ◽  
Laser Fluence ◽  
Femtosecond Laser Ablation ◽  
Temperature Model ◽  
Metal Target ◽  
Temperature Dependent ◽  
Two Temperature

AbstractAn improved two-temperature model to describe femtosecond laser ablation of metal target was presented. The temperature-dependent heat capacity and thermal conductivity of the electron, as well as electron temperature-dependent absorption coefficient and absorptivity are all considered in this two-temperature model. The tailored two-temperature model is solved using a finite difference method for copper target. The time-dependence of lattice and electron temperature of the surface for different laser fluence are performed, respectively. The temperature distribution of the electron and lattice along with space and time for a certain laser fluence is also presented. Moreover, the variation of ablation rate per pulse with laser fluence is obtained. The satisfactory agreement between our numerical results and experimental data indicates that the temperature dependence of heat capacity, thermal conductivity, absorption coefficient and absorptivity in femtosecond laser ablation of metal target must not be neglected. The present model will be helpful for the further experimental investigation of application of the femtosecond laser.

Insights into the surface responses of graphene oxide irradiated by an infrared femtosecond laser

2021 ◽  
Author(s):  
Ye Ding ◽  
Qiang Li ◽  
Jingyi Li ◽  
Lianfu Wang ◽  
Lijun Yang
Keyword(s):  
Graphene Oxide ◽  
Femtosecond Laser ◽  
Electron Density ◽  
Free Electron ◽  
Electrical Response ◽  
Temporal Distribution ◽  
Femtosecond Laser Irradiation ◽  
Time Step ◽  
Free Electron Density ◽  
Wide Range

Abstract Graphene oxide (GO) has emerged as unique and multifaceted novel material with a wide range of applications in electrochemistry and optoelectronic engineering. In these applications, GO surface is characterized with different functional structures in the micro-nano scale, while the femtosecond laser is a promising and versatile tool for manufacturing these structures comparing with conventional approaches. However, the comprehensive surface responses and corresponding regimes of GO surface under femtosecond laser irradiation are not yet identified, which creates obstacles to the further application of femtosecond laser in programming GO surface with specific nanopatterns. Herein, theoretical models characterizing the electrical response, i.e., the transient spatial and temporal distribution of infrared femtosecond laser-excited free electron density at the GO surface layers are established. The numerical simulations are carried out using the discontinuous Galerkin finite element algorithm with a 5 fs time step. The relationship between the laser polarized electric field and free electron density is revealed. On this basis, the surface plasma distribution is characterized, the accuracy of which is verified through the comparison of experimental ablation morphology. Thermal, morphological and chemical responses of the GO surface using different parameters are analyzed correspondingly, from which the formation and evolution mechanisms of surface nanopatterns with different features are explained. This work offers a new insight into the fundamental regimes and feasibility of ultrafast patterning of GO for the application of multifunctional device engineering.

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