Energy exchange between the lattice and electrons in a metal under femtosecond laser irradiation

Petrov, Yu. V.

doi:10.1017/s0263034605050391

Cited by 23 publications

(12 citation statements)

References 8 publications

(3 reference statements)

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“…Von Neumann boundary conditions were used at the top and bottom surfaces of a thin gold film. With a constant electron number density of 5:9 Â 10 28 m À3 , 8,28) it was assumed that the electron and lattice temperatures (300 K) were initially in thermal equilibrium. The film thickness was 300 nm and the laser pulse was 100 fs for the calculation at a fixed wavelength of 1053 nm.…”

Section: )mentioning

confidence: 99%

Comparison of Theoretical Models of Electron-Phonon Coupling in Thin Gold Films Irradiated by Femtosecond Pulse Lasers

2011

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This study reports on a comparison of theoretical models for electron-phonon coupling that is substantially associated with nonequilibrium energy transport in thin gold films irradiated by femtosecond pulse lasers. Three published electron-phonon coupling models were analyzed with the use of a well-established two-temperature model to describe non-equilibrium energy transport between electrons and phonons. Based on the numerical results, at lower fluence, all models showed nearly similar tendencies, whereas at higher fluence, constant electronphonon coupling forced unrealistically long electron-phonon equilibration times and spatially long diffusive regions as it failed to intrinsically consider the effect of a high number density of excited d-band electrons. Even at higher fluence, however, both Lin's and Chen's models yielded physically reasonable results, showing converging electron-phonon equilibration times and steep gradients in the spatial lattice temperature profiles at higher laser fluence. In particular, Lin's model predicts nonlinear characteristics of heat capacity and lattice temperature with respect to laser fluence better than Chen's model. Moreover, the electron-phonon relaxation time increased with laser fluence, whereas at laser fluence greater than 0.05 J/cm 2 , the thermal equilibrium time was nearly independent of the laser fluence. Thus, it was concluded that Lin's model better predicted the electron-phonon coupling phenomena in thin metal films irradiated by ultra-short pulse lasers.

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Section: )mentioning

confidence: 99%

Comparison of Theoretical Models of Electron-Phonon Coupling in Thin Gold Films Irradiated by Femtosecond Pulse Lasers

2011

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“…The electron-ion energy coupling coefficient α is taken from Ref. [14], similar to the one used in Ref. [15].…”

Section: Modeling Methods and Resultsmentioning

confidence: 99%

Ultrashort elastic and plastic shockwaves in aluminum

Inogamov

Хохлов

Petrov

et al. 2012

AIP Conference Proceedings

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Abstract. Ultrashort shock waves in aluminum films generated by femtosecond laser pulses were studied using two-temperature hydrodynamics and molecular dynamics methods. We observed double wave breaking characterized by an independent formation of leading elastic and trailing plastic shock waves. Both the amplitude and speed of the plastic shock decrease quickly in time due to hydrodynamic attenuation, while the elastic shock front slowly decays during propagation. When the pressure in the plastic front becomes equal to the normal component of pressure tensor in the elastic zone, the plastic wave disappears. Therefore, the distance between elastic and plastic fronts first decreases, then increases, with time. The elastic shock uniaxially compresses the crystal to pressures higher than the Hugoniot elastic limit (HEL). For a short time, the crystal within the elastic zone remains in a metastable state, that lies on an extension of the elastic branch of the Hugoniot beyond the HEL. Our theoretical results explain the seemingly puzzling experimental findings, where high-pressure elastic shock waves were observed with normal pressures up to 10-20 GPa.

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“…4 has been calculated in [16] with the use of approach [18,19]. It should be mentioned, that very different approaches [15] and [16] give similar results for the coefficient α of Al, see Fig. 4.…”

Section: As For Eos Of Lif We Present Ionic Part Of Eos As E I (T I mentioning

confidence: 92%

“…4 electron-phonon coupling factor α for LiF is shown together with its value for a simple metal such as Al for the comparison. Coefficients α for aluminum, shown as the curves "Al, 2005" [15] in Fig. 4 were calculated taking into account Thomas-Fermi screening of Coulomb interaction without the use of any adjustable parameters.…”

Section: As For Eos Of Lif We Present Ionic Part Of Eos As E I (T I mentioning

confidence: 99%

Two‐Temperature Warm Dense Matter Produced by Ultrashort Extreme Vacuum Ultraviolet‐Free Electron Laser (EUV‐FEL) Pulse

Inogamov

Faenov

Zhakhovsky

et al. 2011

Contrib. Plasma Phys.

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Key words Short EUV and X-ray laser pulse, LiF ablation, material strength in laser experiment.Ultrashort X-ray laser pulse acts onto electron subsystem of dielectrics such as LiF and transfers matter into a two-temperature state with hot electrons excited by the pulse from valence to conduction band. Because of the small heat conduction, the hydrodynamic motion proceeds in adiabatic regime keeping the radiation attenuation depth Datt as the only scale of the spatial heat distribution. Hydrodynamic motion qualitatively changes with absorbed energy increase. At low fluences F ∼ 10mJ/cm 2 a spallative removal of LiF remaining in solid state takes place. This is a reason for the low ablation threshold. The paper presents new experimental findings supporting this conclusion. For the first time these findings are obtained using ultrashort extreme vacuum ultraviolet-free electron laser (EUV-FEL). In the case of high fluence, also achieved in our experiments at EUV-FEL, material removal happens as result of outflow of matter transferred into the gaseous state. This explains the slow growth of the amount of ablated mass with significant fluence increase.

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Energy exchange between the lattice and electrons in a metal under femtosecond laser irradiation

Cited by 23 publications

References 8 publications

Comparison of Theoretical Models of Electron-Phonon Coupling in Thin Gold Films Irradiated by Femtosecond Pulse Lasers

Comparison of Theoretical Models of Electron-Phonon Coupling in Thin Gold Films Irradiated by Femtosecond Pulse Lasers

Ultrashort elastic and plastic shockwaves in aluminum

Two‐Temperature Warm Dense Matter Produced by Ultrashort Extreme Vacuum Ultraviolet‐Free Electron Laser (EUV‐FEL) Pulse

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