Soft picosecond X-ray laser nanomodification of gold and aluminum surfaces

ピコ秒軟X線レーザーによる金とアルミニウムのナノ構造変化

Starikov, S. V.*; Faenov, A. Ya.; Pikuz, T. A.; Skobelev, I. Yu.*; Fortov, V. E.*; 保 智己*; 石野 雅彦; 田中 桃子; 長谷川 登; 錦野 将元; 海堀 岳史; 今園 孝志; 神門 正城; 河内 哲哉

Starikov, S. V.*; Faenov, A. Ya.; Pikuz, T. A.; Skobelev, I. Yu.*; Fortov, V. E.*; Tamotsu, Satoshi*; Ishino, Masahiko; Tanaka, Momoko; Hasegawa, Noboru; Nishikino, Masaharu; Kaihori, Takeshi; Imazono, Takashi; Kando, Masaki; Kawachi, Tetsuya

The laser pulse modification of surface is investigated for aluminum and gold by experimental and theoretical methods. The surface modification after laser irradiation can be caused by ablation and melting. At low energy of laser pulse, the nanoscale ripples on surface may be induced by the melting without laser ablation. The nanoscale changes of the surface are due to the splash of molten metal under fluence gradient of the laser beam. The ablation process occurs at higher pulse energy when acrater is formed on the surface. It is interesting that the melting is responsible for the size of the modification spot for all range of the energies. We use atomistic simulation of melting and ablation for calculation of threshold fluences and interpretation of the experimental data.