Observation of femtosecond laser ablation process on Tungsten by using a soft X-ray laser probe

Nishikino, Masaharu; Hasegawa, Noboru; Tomita, Takuro*; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Onishi, Naofumi*; Ito, Atsushi*; Baba, Motoyoshi*; Minami, Yasuo*; Inogamov, N.*; Faenov, A.*; Kawachi, Tetsuya; Yamagiwa, Mitsuru; Suemoto, Toru*

Femtosecond laser ablation processes on gold and tungsten were observed by the single shot pump and probe imaging using a soft X-ray laser probe. A clear difference was found in the temporal behavior of the dynamical response of the soft X-ray reflectivity depending on the irradiated laser fluence in two materials. The duration of the femtosecond laser ablation on the tungsten is shorter than the gold case and the narrow dark rings around the crater position were found in the tungsten case. Our experimental data lead to better understanding of the initial process of the laser ablation dynamics.