Observation of dynamics and modification of solid surface using a picosecond soft X-ray laser

Nishikino, Masaharu; Kawachi, Tetsuya; Hasegawa, Noboru; Ishino, Masahiko; Minami, Yasuo*; Suemoto, Toru*; Onishi, Naofumi*; Ito, Atsushi*; Sato, Katsutoshi*; Faenov, A.*; et al.

X-Ray Lasers and Coherent X-Ray Sources; Development and Applications XI (Proceedings of SPIE, Vol.9589), p.958902_1 - 958902_7, 2015/09

Observation of the dependence on the fluence and materials in femto-second laser ablation process by using the soft X-ray laser probe

Hasegawa, Noboru; Tomita, Takuro*; Nishikino, Masaharu; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Minami, Yasuo*; Baba, Motoyoshi*; Onishi, Naofumi*; Ito, Atsushi*; Kawachi, Tetsuya; et al.

JAEA-Conf 2015-001, p.17 - 20, 2015/07

https://jopss.jaea.go.jp/pdfdata/JAEA-Conf-2015-001.pdf#page=27

We have succeeded in simultaneous observation of the ablation front and the expansion front with thin filmy structure in the femto-second laser ablation process of a gold target by using the 13.9 nm soft X-ray probe (incident angle to the sample 70 deg) with soft X-ray interferometer. The dependence on the laser local fluence and materials was obtained by the comparison between gold and tungsten.

Observation of femtosecond laser ablation on Tungsten by using soft X-ray reflection and interference imaging

Nishikino, Masaharu; Hasegawa, Noboru; Tomita, Takuro*; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Onishi, Naofumi*; Ito, Atsushi*; Baba, Motoyoshi*; Minami, Yasuo*; Kawachi, Tetsuya; et al.

Reza Gakkai Dai-471-Kai Kenkyukai Hokoku; Tanhacho Ryoshi Bimu Hassei To Sono Oyo, p.9 - 12, 2014/12

no abstracts in English

Ion transport across a bilayer lipid membrane in the presence of hydrophobic ions

Shirai, Osamu*; Ozaki, Shunsuke*; Onishi, Jun*; Kozai, Naofumi; Onuki, Toshihiko; Kano, Kenji*

Chemistry Letters, 38(11), p.1038 - 1039, 2009/11

https://doi.org/10.1246/cl.2009.1038

Potential-controlled electrolysis was performed between two aqueous phases containing 0.1 M NaCl across a bilayer lipid membrane in the presence of dipicrylaminate (DPA). By use of radioisotope (Na), it has been confirmed that Na is transported mainly and that DPA serves as a carrier of Na transport.

Observation of the femto-second laser ablation on metal surface using X-ray laser, 2

Nishikino, Masaharu; Hasegawa, Noboru; Tomita, Takuro*; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Onishi, Naofumi*; Hatomi, Daiki*; Ito, Atsushi*; Minami, Yasuo*; Takei, Ryota*; et al.

no journal, , 

no abstracts in English

Observation of Weakly Excited Ablation Dynamics with Femtosecond Laser by using Time-Resolved Soft X-ray Imaging Technique

Nishikino, Masaharu; Hasegawa, Noboru; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Tomita, Takuro*; Hatomi, Daiki*; Onishi, Naofumi*; Ito, Atsushi*; Minami, Yasuo*; Baba, Motoyoshi*; et al.

no journal, , 

The dynamical process of laser-induced surface modification such as the laser ablation comes to attract much attention for the micro processing by the ultra-short laser pulse. In order to observe the surface morphological change during the fs laser ablation process with a weakly excitation, we have developed soft X-ray interferometer and reflectometer system. Weakly excited ablation processes of the gold (Au) films are investigated by using single shot pump and probe imaging technique, using a Ti:Sapphire laser pulse with the duration of 80 fs pulse at a central wavelength of 795 nm for the pumping of ablation and the laser-driven soft X-ray laser at the wavelength of 13.9 nm for the probe. We discuss the scenario of the weakly excited femtosecond laser ablation of the gold surface. The numerical simulation study of the fs laser ablation process is underway by using a parallel molecular dynamics code.

A Study of the femto-second laser ablation process in metals by using a soft X-ray laser probe

Hasegawa, Noboru; Nishikino, Masaharu; Kawachi, Tetsuya; Yamagiwa, Mitsuru; Tomita, Takuro*; Suemoto, Toru; Onishi, Naofumi*; Ito, Atsushi*; Baba, Motoyoshi*; Minami, Yasuo*

no journal, , 

We have succeeded in simultaneous observation of temporal evolution of two different surfaces of the femto-second laser ablation process of metals (Au) by using the soft X-ray laser probe. The ablation front with a solid or the liquid surface and the expansion front with thin film structure were observed from the results of the soft X-ray interferogram, reflective imaging and shadowgraph. The expansion front separated from the ablation front was thin, dense and smooth so as to work as the beam splitter for the soft X-rays at the time within 1 ns after the laser irradiation. The expansion front that included almost all of the mass of the crater inside was kept at the time around 1 microsecond, and the height of that reached over 100 micron. From these results, the ablation front gradually becomes vapor while maintaining a clear and smooth expansion front.

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.*; et al.

no journal, , 

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.

Observation of the femto-second laser ablation process on metal surface using the soft X-ray laser probe

Yamagiwa, Mitsuru; Hasegawa, Noboru; Nishikino, Masaharu; Tomita, Takuro*; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Onishi, Naofumi*; Hatomi, Daiki*; Ito, Atsushi*; Minami, Yasuo*; et al.

no journal, , 

no abstracts in English

Time resolved observation of the femto-second laser ablation dynamics by using the soft X-ray probe

Hasegawa, Noboru; Nishikino, Masaharu; Tomita, Takuro*; Takei, Ryota*; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Hatomi, Daiki*; Onishi, Naofumi*; Baba, Motoyoshi*; Kawachi, Tetsuya; et al.

no journal, , 

We have observed the temporal evolution of the femto-second laser irradiated metal surface by using the soft X-ray laser probe at the wavelength of 13.9 nm. The initial dynamics of the fs-laser ablation is quite rapid ( a few ps) and the dynamics of the laser processing is kept for a long time. We have developed a new pump and probe system to measure these phenomena by the same set-up. By using this system, we have succeeded to obtain the temporal evolution of the ablation front exfoliated from the laser ablated gold surface.