M. Povarnitsyn, K. Khishchenko, P. Levashov A wide-range model for simulation of pump-probe experiments with metals M. Povarnitsyn, K. Khishchenko, P. Levashov Joint Institute for High Temperatures RAS, Moscow, Russia povar@ihed.ras.ru T. Itina Laboratoire Hubert Curien, CNRS, St-Etienne, France EMRS-2011 Laser materials processing for micro and nano applications Nice, France 12 May, 2011

Outline Motivation Model — Governing equations — Equation-of-state — Transport properties Pump-probe technique Simulation results Conclusions

Motivation Reflectivity R Phase shift ψ

Two-temperature hydrodynamic model

Two-temperature semi-empirical EOS bn unstable sp

Frequency of collisions Eidmann et al. PRE 62 (2000) Pump-probe for cold Elsayed et al. PRL 58, 1212 (1987) Groeneveld et al. PRL 64, 784 (1990) Schoenlein et al. PRL 58, 1680 (1987)

Electron-ion coupling model

Electron-ion coupling

Thermal conductivity model

Thermal conductivity of Al, Ti = Te

Permittivity model

Permittivity of Al, Ti = Troom E. D. Palik, Handbook of optical constants of solids, 1985.

Equations of EM field

Transfer-matrix method (optics) Born, M.; Wolf, E., Oxford, Pergamon Press, 1964.

Energy absorption

Widmann et al. PHYSICS OF PLASMAS 8 (2001) Pump-probe technique pump probe CCD delay target Widmann et al. PHYSICS OF PLASMAS 8 (2001)

Reflectivity of S- and P-polarized probes

Phase shift of S- and P-polarized probes

Conclusions Pump-probe experiments provide an integral test of the models in the theoretically difficult regime of warm dense matter The target material motion is evident for heating by femtosecond pulses of intensity > 1014 W/cm2. Phase shift of S and P-polarized pulses is different because of separated zones of absorption Uncertainty in the pulse energy determination of ~ 10% gives substantial deflection of the theoretical curves

Appendix

Appendix