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The microscopic mechanism of metal ablation induced by ultrashort laser pulse irradiation is investigated. A two-temperature model scheme combined with molecular dynamics (TTM-MD) is developed to incorporate electronic entropy effects into…
Laser ablation is often explained by a two-temperature model (TTM) with different electron and lattice temperatures. To realize a classical molecular dynamics simulation of the TTM, we propose an extension of the embedded atom method to…
The femtosecond laser pulse heating of silver film is investigated by performing quantum mechanics (QM), molecular dynamics (MD) and two temperature model (TTM) integrated multiscale simulation. The laser excitation dependent electron…
The mechanism of ablation of solids by intense femtosecond laser pulses is described in an explicit analytical form. It is shown that at high intensities when the ionization of the target material is complete before the end of the pulse,…
Laser pulses with a duration of the order of femtoseconds lead to a strong excitation, heating and potentially to ablation of the irradiated material. During the time of strong excitation, the interaction of the atoms and thus the material…
Femtosecond (fs) laser sintering enables ultrafast and spatially localized energy deposition, making it attractive for additive manufacturing of metal nanoparticles. However, undesired ablation during fs irradiation of copper (Cu)…
By combining ab initio quantum mechanics calculation and Drude model, electron temperature and lattice temperature dependent electron thermal conductivity is calculated and implemented into a multiscale model of laser material interaction,…
The electronic behavior of various solid metals (Al, Ni, Cu, Au, Ti, and W) under ultrashort laser irradiation is investigated by means of density functional theory. Successive stages of extreme nonequilibrium on picosecond time scale…
Ablation of Cu and Al targets has been performed with 170 fs laser pulses in the intensity range of 10^12-10^14 W/cm^2. We compare the measured removal depth with 1D hydrodynamic simulations. The electron-ion temperature decoupling is taken…
We compute the thermodynamic phase diagram of seventeen elemental metals with hexagonal close-packed (hcp), face-centered cubic (fcc), and body-centered cubic (bcc) crystal structures using finite-temperature density functional theory.…
Using ordinary Fourier analysis, the asymptotic decay behavior of the density matrix F(r,r') is derived for the case of a metal at a finite electronic temperature. An oscillatory behavior which is damped exponentially with increasing…
The modern means of controlled irradiation by femtosecond lasers or swift heavy ion beams can transiently produce such energy densities in samples that reach collective electronic excitation levels of the warm dense matter state where the…
Ultrafast laser excitation can induce fast increases of the electronic subsystem temperature. The subsequent electronic evolutions in terms of band structure and energy distribution can determine the change of several thermodynamic…
The electronic friction-Langevin dynamics (EF-LD) offers a simplified framework for describing nonadiabatic effects at metal surfaces, particularly in electrochemical and molecular electronic applications. We investigate the electronic…
Ultrafast laser heating of electrons on a metal surface breaks the pressure equilibrium within the material, thus initiating ablation. The stasis of a room-temperature metal results from a balance between repulsive and attractive binding…
The temperature dependence of most solid-state properties is dominated by lattice vibrations, but metals display notable purely electronic effects at low temperature, such as the linear specific heat and the linear entropy, that were…
We investigate a temperature-based model, called extended two-temperature model (eTTM), that describes the electronic non-equilibrium and its effect on energy dissipation in metals after ultrashort laser excitation. We derive and discuss…
A numerical hydrodynamic study of femtosecond laser ablation is presented. A detailed analysis of material decomposition is performed using a thermodynamically complete equation of state with separate stable and metastable phase states and…
The physical mechanisms for damage formation in graphite films induced by femtosecond laser pulses are analyzed using a microscopic electronic theory. We describe the nonequilibrium dynamics of electrons and lattice by performing molecular…
We investigated femtosecond laser ablation dynamics using THz time-domain spectroscopy. To clarify the breakdown dynamics of materials, we focused on the motion of charged particles and measured the terahertz waves emitted during laser…