Publications

2014

• Characterization of laser-driven ultrafast shockless compression using gold targets
  
  • Miyanishii K.
  • Ozaki N.
  • Brambrink E.
  • Amadou N.
  • Benuzzi-Mounaix A.
  • Cauble R.
  • Diziere A.
  • Guyot F.
  • Koenig M.
  • Morard Guillaume
  • de Resseguier T.
  • Ravasio A.
  • Smith R.
  • Tange Y.
  • Vinci T.
  • G. Wei H.
  • Kodama R.
  Journal of Applied Physics, American Institute of Physics, 2014, 118, pp.043521. Indirect laser-driven shockless compression experiments on gold targets were performed to characterize pressure loading processes and target states. Free surface velocities of the gold target under ramped pressure loading were measured using line-imaging velocity interferometers. From the velocity data and the equation of state, the maximum pressure and strain rate attained under compression were estimated to be 50 GPa and 4 107 s 1, respectively. Optical reflectivity was measured simultaneously with the velocity, the result suggesting no significant or unexpected temperature increases in the ultrafast shockless compression process (10.1063/1.4891802)
  DOI : 10.1063/1.4891802
• Density measurements and structural properties of liquid and amorphous metals under high pressure
  
  • Morard Guillaume
  • Garbarino G.
  • Antonangeli D.
  • Andrault Denis
  • Guignot N.
  • Siebert J.
  • Roberge M.
  • Boulard E.
  • Lincot A.
  • Denoeud A.
  • Petitgirard S.
  High Pressure Research, Taylor & Francis, 2014, pp.1. We have implemented an in situ X-ray diffraction analysis method suitable for the determination of pressure-volume-temperature equations of state in the critical case of liquid and amorphous materials over an extended thermodynamic range (T > 2000K and P > 40 GPa). This method is versatile, it can be applied to data obtained using various angle-dispersive X-ray diffraction high pressure apparatus and, contrary to in situ X-ray absorption techniques, is independent from the sample geometry. Further advantage is the fast data acquisition (between 10 and 300 s integration time). Information on macroscopic bulk properties (density) and local atomic arrangement (pair distribution function g(r)) can be gathered in parallel. To illustrate the method, we present studies on liquid Fe-S alloys in the Paris Edinburgh press and in laser-heated diamond anvil cell (DAC), and measurements on Ce glass in DAC at room temperature (10.1080/08957959.2013.860137)
  DOI : 10.1080/08957959.2013.860137
• Ab initio calculation of x-ray absorption of iron up to 3 Mbar and 8000 K
  
  • Mazevet Stéphane
  • Recoules Vanina
  • Bouchet Johan
  • Guyot François
  • Harmand M.
  • Ravasio Alessandra
  • Benuzzi-Mounaix Alessandra
  Physical Review B, American Physical Society, 2014, 89. Using ab initio simulations within the generalized gradient approximation, we calculate x-ray absorption near edge spectra (XANES) at the iron K edge throughout the high-pressure phase diagram and up to extreme density and temperature conditions that are representative of the Earth's inner core (up to 3 Mbar and 8000 K). We show that XANES spectra near the Fe K edge exhibit clear signatures for the different high-temperature, high-pressure phases of iron. This suggests that XANES spectroscopy might be used to resolve ongoing controversies regarding both the high-pressure melting curve of iron and the nature of the solid phases undergoing melting up to several Mbar. In contrast to diffraction measurements, it also offers a severe constraint for density functional theory predictions of the transport properties of iron by providing direct information on the electronic structure of iron at these extreme conditions. (10.1103/PhysRevB.89.100103)
  DOI : 10.1103/PhysRevB.89.100103
• Ultra-short pulse laser-induced damage thresholds of broadband high-reflective and low dispersive coatings
  
  • Hervy Adrien
  • Chériaux Gilles
  • Gallais Laurent
  • Mouricaud Daniel
  • Utéza Olivier
  • Clady R.
  • Sentis Marc
  • Freneaux Antoine
  , 2014.
• Metallization of warm dense SiO$_2$ studied by XANES spectroscopy
  
  • Denoeud A.
  • Benuzzi-Mounaix A.
  • Ravasio A.
  • Dorchies F.
  • Leguay P. M.
  • Gaudin J.
  • Guyot F.
  • Brambrink E.
  • Koenig M.
  • Le Pape S.
  • Mazevet S.
  Physical Review Letters, American Physical Society, 2014, 113 (11), pp.116404. We investigate the evolution of the electronic structure of fused silica in a dense plasma regime using time-resolved x-ray absorption spectroscopy. We use a nanosecond (ns) laser beam to generate a strong uniform shock wave in the sample and a picosecond (ps) pulse to produce a broadband x-ray source near the Si $K$ edge. By varying the delay between the two laser beams and the intensity of the ns beam, we explore a large thermodynamical domain with densities varying from 1 to 5 g/cm$^3$ and temperatures up to 5 eV. In contrast to normal conditions where silica is a well-known insulator with a wide band gap of 8.9 eV, we find that shocked silica exhibits a pseudogap as a semimetal throughout this thermodynamical domain. This is in quantitative agreement with density functional theory predictions performed using the generalized gradient approximation. (10.1103/PhysRevLett.113.116404)
  DOI : 10.1103/PhysRevLett.113.116404
• Thin films characterizations to design high-reflective coatings for ultrafast high power laser systems
  
  • Hervy Adrien
  • Gallais Laurent
  • Mouricaud Daniel
  • Chériaux Gilles
  • Utéza Olivier
  • Clady R.
  • Sentis Marc
  • Freneaux Antoine
  , 2014, 9237, pp.92370J.