Modified molecular dynamics simulation on ultrafast laser ablation of metal

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Recently, short-pulse lasers have been applied to microfabrication in the field of various industries. It becomes more difficult to experimentally observe the microfabrication phenomena as pulse width becomes short. Numerical analysis with a continuum model has a limit in elucidation of such phenomena, therefore, computer simulations at the atomic or molecular level must be important. The authors have conducted the molecular dynamics simulation of laser materials processing over the years. In this paper, a modified molecular dynamics method for metal developed by the authors, where calculation of the molecular dynamics is carried out while revising the heat conduction by free electrons at each time step, was applied to elucidate the laser microfabrication phenomena. Pulse width dependence of damage threshold, evaporation process, velocity distribution of evaporation particles and temperature profile near the surface were investigated.Recently, short-pulse lasers have been applied to microfabrication in the field of various industries. It becomes more difficult to experimentally observe the microfabrication phenomena as pulse width becomes short. Numerical analysis with a continuum model has a limit in elucidation of such phenomena, therefore, computer simulations at the atomic or molecular level must be important. The authors have conducted the molecular dynamics simulation of laser materials processing over the years. In this paper, a modified molecular dynamics method for metal developed by the authors, where calculation of the molecular dynamics is carried out while revising the heat conduction by free electrons at each time step, was applied to elucidate the laser microfabrication phenomena. Pulse width dependence of damage threshold, evaporation process, velocity distribution of evaporation particles and temperature profile near the surface were investigated.