Dynamics of plume and crater formation after action of femtosecond laser pulse

Агранат, М. Б.; Анисимов, С. И.; Ашитков, С. И.; Жаховский, В. В.; Inogamov, N. A.; Nishihara, Katsunobu; Petrov, Yu. V.; Фортов, В. Е.; Khokhlov, Victor

doi:10.1016/j.apsusc.2007.01.077

Cited by 58 publications

(31 citation statements)

References 15 publications

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“…The results of earlier MD simulations of laser irradiation of bulk molecular targets, 16,17,29,67 metal films, 50,68-70 bulk metal targets, 16,71 and systems where interatomic interaction is described by LennardJones potential [72][73][74] suggest that the photomechanical spallation is a general process that can occur in a wide class of materials and different types of targets. The mechanisms of spallation are found to be similar in molecular and metal targets and are described in detail in ref 16.…”

Section: From Melting To Spallation and Phase Explosionmentioning

confidence: 99%

“…The transition from spallation to phase explosion can also be related to the experimental observation of the disappearance of optical interference patterns (Newton rings), observed in pump-probe experiments, 74,82 with an increase in laser fluence. The observation of the Newton rings has been explained by the spallation of a thin liquid layer from the irradiated target, 16,73,83 whereas the disappearance of the interference fringes in the central part of the laser spot 74 may be related to the transition to the phase explosion regime.…”

Section: From Melting To Spallation and Phase Explosionmentioning

confidence: 99%

“…The observation of the Newton rings has been explained by the spallation of a thin liquid layer from the irradiated target, 16,73,83 whereas the disappearance of the interference fringes in the central part of the laser spot 74 may be related to the transition to the phase explosion regime.…”

Section: From Melting To Spallation and Phase Explosionmentioning

confidence: 99%

See 2 more Smart Citations

Atomistic Modeling of Short Pulse Laser Ablation of Metals: Connections between Melting, Spallation, and Phase Explosion

2009

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The mechanisms of short pulse laser interactions with a metal target are investigated in simulations performed with a model combining the molecular dynamics method with a continuum description of laser excitation, electron-phonon equilibration, and electron heat conduction. Three regimes of material response to laser irradiation are identified in simulations performed with a 1 ps laser pulse, which corresponds to the condition of stress confinement: melting and resolidification of a surface region of the target, photomechanical spallation of a single or multiple layers or droplets, and an explosive disintegration of an overheated surface layer (phase explosion). The processes of laser melting, spallation, and phase explosion are taking place on the same time scale and are closely intertwined with each other. The transition to the spallation regime results in a reduction of the melting zone and a sharp drop in the duration of the melting and resolidification cycle. The transition from spallation to phase explosion is signified by an abrupt change in the composition of the ejected plume (from liquid layers and/or large droplets to a mixture of vapor-phase atoms, small clusters and droplets), and results in a substantial increase in the duration of the melting process. In simulations performed with longer, 50 ps, laser pulses, when the condition for stress confinement is not satisfied, the spallation regime is absent and phase explosion results in smaller values of the ablation yield and larger fractions of the vapor phase in the ejected plume as compared to the results obtained with a 1 ps pulse. The more vigorous material ejection and higher ablation yields, observed in the simulations performed with the shorter laser pulse, are explained by the synergistic contribution of the laser-induced stresses and the explosive release of vapor in phase explosion occurring under the condition of stress confinement.

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Section: From Melting To Spallation and Phase Explosionmentioning

confidence: 99%

Section: From Melting To Spallation and Phase Explosionmentioning

confidence: 99%

See 1 more Smart Citation

Atomistic Modeling of Short Pulse Laser Ablation of Metals: Connections between Melting, Spallation, and Phase Explosion

2009

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“…Above this limit, cohesive property is weak against strong stretching in a hydrodynamic rarefaction waveexpansion proceeds similar to expansion of heated gas (that is, without spallative plate). The cohesive property is responsible for creation of a spallative plate and spallative cupola [16]. The cupola is necessary for the interference which results in appearance of the varying in time Newton rings [16].…”

Section: Introductionmentioning

confidence: 99%

“…The cohesive property is responsible for creation of a spallative plate and spallative cupola [16]. The cupola is necessary for the interference which results in appearance of the varying in time Newton rings [16].…”

Section: Introductionmentioning

confidence: 99%

Spallative ablation of dielectrics by X-ray laser

et al. 2010

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Short laser pulse in wide range of wavelengths, from infrared to X-ray, disturbs electron-ion equilibrium and rises pressure in a heated layer. The case where pulse duration τ L is shorter than acoustic relaxation time t s is considered in the paper. It is shown that this short pulse may cause thermomechanical phenomena such as spallative ablation regardless to wavelength. While the physics of electron-ion relaxation strongly depends on wavelength and various electron spectra of substances: there are spectra with an energy gap in semiconductors and dielectrics opposed to gapless continuous spectra in metals. The paper describes entire sequence of thermomechanical processes from expansion, nucleation, foaming, and nanostructuring to spallation with particular attention to spallation by X-ray pulse.

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Electron‐Ion Relaxation, Phase Transitions, and Surface Nano‐Structuring Produced by Ultrashort Laser Pulses in Metals

Inogamov

Zhakhovsky

Petrov

et al. 2013

Contrib. Plasma Phys.

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Fundamental physical phenomena in metals irradiated by ultrashort laser pulses with absorbed fluences higher than few tens of mJ/cm2 are investigated. For those fluences, laser‐produced electron distribution function relaxes to equilibrium Fermi distribution with electron temperature Te within a short time of 10‐100 fs. Because the electron subsystem has Te highly exceeding much the ion subsystem temperature Ti the well‐known twotemperature hydrodynamic model (2T‐HD) is used to evaluate heat propagation associated with hot conductive electron diffusion and electron‐ion energy exchange. The model coefficients of electron heat conductivity κ (ϱ, Te, Ti) and electron‐ion coupling parameter α (ϱ, Te) together with 2T equation of state E (ϱ, Te, Ti) and P (ϱ, Te, Ti) are calculated. Modeling with 2T‐HD code shows transition of electron heat wave from supersonic to subsonic regime of prop‐agation. At the moment of transition the heat wave emits a compression wave moving into the bulk of met al. Nonlinear evolution of the compression wave after its separation from the subsonic heat wave till spallation of rear‐side layer of a film is traced in both 2T‐HD modeling and molecular dynamics (MD) simulation. For fluences above some threshold the nucleation of voids in frontal surface layer is initiated by strong tensile wave following the compression wave. If the absorbed fluence is ∼30 % above the ablation threshold than void nucleation develops quickly to heavily foam the molten met al. Long‐term evolution of the metal foam including foam breaking and freezing is simulated. It is shown that surface nano‐structures observed in experiments are produced by very fast cooling of surface molten layer followed by recrystallization of supercooled liquid in disintegrating foam having complex geometry. Characteristic lengths of such surface nanostructures, including frozen pikes and bubbles, are of the order of thickness of molten layer formed right after laser irradiation. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Dynamics of plume and crater formation after action of femtosecond laser pulse

Cited by 58 publications

References 15 publications

Atomistic Modeling of Short Pulse Laser Ablation of Metals: Connections between Melting, Spallation, and Phase Explosion

Atomistic Modeling of Short Pulse Laser Ablation of Metals: Connections between Melting, Spallation, and Phase Explosion

Spallative ablation of dielectrics by X-ray laser

Electron‐Ion Relaxation, Phase Transitions, and Surface Nano‐Structuring Produced by Ultrashort Laser Pulses in Metals

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