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石野 雅彦; Faenov, A.*; 田中 桃子; Pikuz, T.; 保 智己*; 長谷川 登; 錦野 将元; Starikov, S. V.*; Stegailov, V. V.*; Norman, G.*; et al.
X-Ray Lasers 2012; Springer Proceedings in Physics, Vol.147, p.121 - 124, 2014/00
被引用回数:0 パーセンタイル:0.00(Engineering, Electrical & Electronic)We show experimentally the possibility of the precise nano-meter size surface structuring of metal surfaces induced by ultra low fluencies of pico-second soft X-ray laser single pulse. After irradiation processes, we observed the modified surfaces to understand the interactions between the soft X-ray laser pulses and various materials by a scanning electron microscope. The formations of unique modified structures caused by irradiations of the soft X-ray laser pulses were seen. On Al surface, the formations of conical structures were observed in the shallow features. On Au surface, the ripple-like structures were observed. The atomistic model of ablation is developed that reveals the ultra-low threshold fluency values of this process. Calculated ablation depth as a function of irradiation fluency is in good agreement with the experimental data presented as well as with the existing data on optical ablation. Our results will open new opportunities for nano-meter size processing for metal surfaces.
石野 雅彦; Faenov, A.*; 田中 桃子; 保 智己*; Pikuz, T.; 長谷川 登; 錦野 将元; Inogamov, N.*; Skobelev, I.*; Fortov, V.*; et al.
Proceedings of SPIE, Vol.8849, p.88490F_1 - 88490F_8, 2013/09
被引用回数:2 パーセンタイル:72.45(Optics)To study the interactions between soft X-ray laser (SXRL) beam and material surfaces, we irradiated the SXRL beam pulses having a wavelength of 13.9 nm and duration of 7 ps to Al, Au, Cu, and Si. Irradiated surfaces were observed using SEM and AFM. With single pulse irradiation, the formation of conical structures was observed on Al, and ripple-like structures were formed on Au and Cu. The conical structures on Al surface were destroyed under the multiple SXRL pulse exposures, but it was confirmed that the development of modified structures was observed after multiple pulse exposures on the Au and Cu surfaces. On the Si surface, deep holes that seemed to be melted structures induced by the accumulation of multiple pulses of irradiations were found. It was concluded that SXRL beam irradiation of various material surfaces causes different types of surface modifications, and the changes in the surface behaviors are attributed to the differences in the elemental properties, such as the melting points and the attenuation length of X-ray photons.
Norman, G.*; Starikov, S.*; Stegailov, V.*; Fortov, V.*; Skobelev, I.*; Pikuz, T.; Faenov, A.*; 保 智己*; 加藤 義章*; 石野 雅彦; et al.
Journal of Applied Physics, 112(1), p.013104_1 - 013104_8, 2012/07
被引用回数:41 パーセンタイル:81.61(Physics, Applied)It was shown experimentally the possibility of nanostructuring (about 20 nm) of gold surface by picosecond soft X-ray single pulse with low fluence of 20 mJ/cm. The nanometer-scale changes of the surface structure are due to the splash of molten gold under fluence gradient of the laser beam. In addition, the ablation process occurs at slightly higher fluence of 50 mJ/cm. The atomistic model of ablation is developed that reveals that the low threshold fluence of this process is due to the build-up of the high electron pressure and the comparatively low electron-ion energy relaxation rate in gold.
Starikov, S. V.*; Stegailov, V. V.*; Norman, G. E.*; Fortov, V. E.*; 石野 雅彦; 田中 桃子; 長谷川 登; 錦野 将元; 大場 俊幸*; 海堀 岳史; et al.
JETP Letters, 93(11), p.642 - 647, 2011/04
被引用回数:25 パーセンタイル:75.00(Physics, Multidisciplinary)The interaction of radiation of a picosecond X-ray laser (wavelength = 13.9 nm) with targets made of a thick gold film has been studied theoretically and experimentally. It has been shown experimentally that the action of individual X-ray laser pulses with a fluence of 21 mJ/cm initiates the nanostructuring of the gold surface. Explicitly taking into account the electron subsystem, we have proposed an atomistic model of ablation that makes it possible to adequately described the experimental results. The atomistic simulation involves the ion-ion potential depending on the electron temperature . The use of such a potential makes it possible to take into account an increase in the pressure in the system with increasing and to reveal two laser ablation mechanisms.
Pikuz, T.; Faenov, A.*; 石野 雅彦; Starikov, S. V.*; Stegailov, V. V.*; Norman, G. E.*; Fortov, V.*; Skobelev, I.*; Inogamov, N. A.*; Zhakhovsky, V. V.*; et al.
no journal, ,
Systematic experimental and theoretical studies of the surface modifications resulting from the interactions of both single and multiple SXRL pulses irradiation of metals have been provided. Developed models show that relatively slow electron-ionic relaxation in such metals results in maintaining of the high electron pressure in the near surface region for several picoseconds, that is sufficiently long for the development of the hydrodynamic response that causes the negative pressure region formation and the nanostructuring of a thin surface layer. Obtained results demonstrate that tensile stress created in metals by short X-ray pulse can produce spallative ablation of target even for drastically small X-ray fluencies, which open new opportunities for material nano processing.
Pikuz, T.; Faenov, A.*; 石野 雅彦; Starikov, S. V.*; Stegailov, V. V.*; Norman, G.*; Fortov, V.*; Skobelev, I.*; 保 智己*; 加藤 義章*; et al.
no journal, ,
We show experimentally the possibility of the precise nanostructuring of aluminum and gold surfaces by ultra low fluencies of single picosecond soft X-ray laser pulse. The atomistic model of ablation is developed that reveals the ultra-low threshold fluency values of this process to be an effect of the high electronic pressure build-up and the comparatively low electron-ion energy relaxation rates. Our modeling show that relatively slow electron-ionic relaxation in such metals results in maintaining of the high electron pressure in the near surface region for several picoseconds, that is sufficiently long for the development of the hydrodynamic response that causes the negative pressure region formation and the nanostructuring of a thin surface layer. Calculated ablation depth as a function of irradiation fluency is in good agreement with the experimental data presented as well as with the existing data on optical ablation.
石野 雅彦; Faenov, A. Ya.*; 田中 桃子; Pikuz, T.; 保 智己*; 長谷川 登; 錦野 将元; Starikov, S. V.*; Stegailov, V. V.*; Norman, G. E.*; et al.
no journal, ,
Laser ablation has many technological applications in material micro-meter size processing and fabrication of nano-structures. We show experimentally the possibility of the precise nano-meter size surface structuring of metal aluminum (Al) and gold (Au) surfaces induced by ultra low fluencies of pico-second soft X-ray laser (SXRL) single pulse. The spatially coherent SXRL beam was generated from the silver (Ag) plasma mediums using oscillator-amplifier configuration with Ag double targets. The generated SXRL pulse had the wavelength of 13.9 nm and the duration of 7 ps. On Al surface, the formations of conical structures were observed in the shallow features. On Au surface, the ripple-like structures were observed. The atomistic model of surface modifications is developed that reveals the ultra-low threshold fluency values of this process and suggests it as a splash-melting regime. Our results will open new opportunities for nano-meter size processing for metal surfaces.
Faenov, A.*; Pikuz, T.; 石野 雅彦; Starikov, S. V.*; Stegailov, V. V.*; Norman, G.*; Fortov, V. E.*; Skobelev, I. Yu.*; 保 智己*; 田中 桃子; et al.
no journal, ,
A systematic experimental study of the surface modifications resulting from the interactions of both single and multiple SXRL pulses in order to confirm the development of the modified structures during multiple shots irradiation. The interactions between single or multiple picosecond soft X-ray laser (SXRL) beam and metal (such as gold (Au), copper (Cu), and aluminum (Al)) surfaces, were investigated. Our results demonstrate that tensile stress created in metals by short X-ray pulse can produce spallative ablation of target even for drastically small X-ray fluencies, which open new opportunities for material nano processing.