title: Dynamical study of femtosecond-laser-ablated liquid-aluminum nanoparticles using spatiotemporally resolved x-ray-absorption fine-structure spectroscopy.
abstract: We study the temperature evolution of aluminum nanoparticles generated by femtosecond laser ablation with spatiotemporally resolved x-ray-absorption fine-structure spectroscopy. We successfully identify the nanoparticles based on the L-edge absorption fine structure of the ablation plume in combination with the dependence of the edge structure on the irradiation intensity and the expansion velocity of the plume. In particular, we show that the lattice temperature of the nanoparticles is estimated from the L-edge slope, and that its spatial dependence reflects the cooling of the nanoparticles during plume expansion. The results reveal that the emitted nanoparticles travel in a vacuum as a condensed liquid phase with a lattice temperature of about 2500 to 4200 K in the early stage of plume expansion.
authors.affiliation: NTT Basic Research Laboratories, Nippon Telegraph and Telephone Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198, Japan. oguri@nttbrl.jp
authors.forename: Katsuya
authors.initials: K
authors.lastname: Oguri
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Okano
authors.forename: Tadashi
authors.initials: T
authors.lastname: Nishikawa
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Nakano