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