Femtosecond laser-induced confined microexplosion: tool for creation high-pressure phases
- PDF / 399,231 Bytes
- 7 Pages / 432 x 648 pts Page_size
- 12 Downloads / 159 Views
Femtosecond laser-induced confined microexplosion: tool for creation high-pressure phases Saulius Juodkazis1, Arturas Vailionis2,3, Eugene G. Gamaly4, Ludovic Rapp4, Vygantas Mizeikis5, Andrei V. Rode4 1 School of Science, Swinburne University of Technology, John st., Hawthorn, Vic 3122, Australia 2 Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, U.S.A. 3 Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, U.S.A. 4 Laser Physics Center, Research School of Physics and Engineering, Australian National University, ACT 0200, Australia 5 Division of Global Research Leaders, (Research Institute of Electronics), Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Japan ABSTRACT New material phases formed under non-equilibrium conditions at pressures above 100 GPa and temperatures exceeding 104K, the conditions of the warm dense matter (WDM), have become accessible using micro-explosions triggered by ultra-short sub-1 ps pulses tightly focused into micro-volume with cross sections comparable with the wavelength of light. Laser-induced micro-explosions convert a material in a focal volume into a non-equilibrium disordered plasma state confined inside the bulk of pristine crystal. Ultra-high quenching rates overcome kinetic barriers to the formation of new metastable high pressure phases, which are preserved in the surrounding pristine crystal for following recovery and exploitation. Direct laser writing was used to pattern large areas by closely packed arrays of the microexplosion modified sites for structural characterisation of the minute volumes of nano-materials with transmission electron microscopy, diffraction and synchrotron X-ray diffraction. The method of ultrafast-laser induced confined microexplosion is demonstrated for modification and creation of new phases in case of bcc-Al inside sapphire, valence change of Fe-ions in olivine, formation of new tetragonal bt8 and st12 phases of silicon, Ge and O separation in GeO2 glass and molecular oxygen formation inside voids at the site of microexplosion inside glasses. INTRODUCTION Investigation of high pressure and temperature phases of different materials are spanning from the fundamental research [1–3] as recently demonstrated metallic bonding in hydrogen [4] to developing new pathways of material synthesis for future practical use [5]. High pressure and temperature transients created by fs-laser pulses at several TW/cm2 makes an optical breakdown driven micro-explosion [6] with conditions referred to as the warm dense matter (WDM) [7–10] where exotic phases of materials are created and can be retrieved due to extremely fast quenching [11, 12]. Formation of voids in materials with the highest bulk modulus exceeding pressures at the Earth’s center can bring new fundamental understanding how high- pressure/temperature materials are formed. Structural modifications inside transparent materials can be controlled down to sub-wavelength resolution
Data Loading...
