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Azuma, Hirozumi*; Sagisaka, Akito; Daido, Hiroyuki; Ito, Isao*; Kadoura, Hiroaki*; Kamiya, Nobuo*; Ito, Tadashi*; Nishimura, Akihiko; Ma, J.*; Mori, Michiaki; et al.
Applied Surface Science, 255(24), p.9783 - 9786, 2009/09
Times Cited Count:2 Percentile:11.75(Chemistry, Physical)Commercial single crystal silicon wafers and amorphous silicon films piled on single crystal silicon wafers were irradiated with a femtosecond pulsed laser and a nanosecond pulsed laser at irradiation intensities between 10 W/cm and 10 W/cm. In the single crystal silicon substrate, the irradiated area was changed to polycrystalline silicon and the piled silicon around the irradiated area has spindly column structures constructed of polycrystalline and amorphous silicon. In particular, in the case of the higher irradiation intensity of 10 W/cm, the irradiated area was oriented to the same crystal direction as the substrate. In the case of the lower irradiation intensity of 10 W/cm, only amorphous silicon was observed around the irradiated area, even when the target was single crystal silicon.
Nishiuchi, Mamiko; Daido, Hiroyuki; Yogo, Akifumi; Orimo, Satoshi; Ogura, Koichi; Ma, J.-L.; Sagisaka, Akito; Mori, Michiaki; Pirozhkov, A. S.; Kiriyama, Hiromitsu; et al.
Physics of Plasmas, 15(5), p.053104_1 - 053104_10, 2008/05
Times Cited Count:45 Percentile:83.73(Physics, Fluids & Plasmas)High-flux energetic protons whose maximum energies are up to 4 MeV are generated by an intense femtosecond Titanium Sapphire laser pulse interacting with a 7.5, 12.5, and 25m thick Polyimide tape targets. The laser pulse energy is 1.7 J, duration is 34 fs, and intensity is 310Wcm. The amplified spontaneous emission (ASE) has the intensity contrast ratio of 410. The conversion efficiency from laser energy into proton kinetic energies of 3% is achieved, which is comparable or even higher than those achieved in the previous works with nanometer-thick targets and the ultrahigh contrast laser pulses (10).
Sagisaka, Akito; Azuma, Hirozumi*; Daido, Hiroyuki; Kamiya, Nobuo*; Ito, Tadashi*; Takeuchi, Akihiro*; Suzuki, Noritomo*; Nishimura, Akihiko; Mori, Michiaki; Orimo, Satoshi; et al.
Proceedings of 4th International Congress on Laser Advanced Materials Processing (LAMP 2006) (Internet), 3 Pages, 2006/00
no abstracts in English
Nishiuchi, Mamiko; Daido, Hiroyuki; Yogo, Akifumi; Orimo, Satoshi; Ogura, Koichi; Ma, J.-L.; Sagisaka, Akito; Mori, Michiaki; Pirozhkov, A. S.; Kiriyama, Hiromitsu; et al.
no journal, ,
The efficient proton beam whose maximum energy of up to 4 MeV was produced by the 50TW short pulse intensity Ti:Sap laser irradiated on the polyimide target [(CHON)n] with the thicknesses of 7.5m, 12.5m, 25m, which is transparent to the 800 nm laser. The laser parameters are energy of 1.7J, pulse width of 35fs and the intensity of 310 Wcm. The contrast of the ASE component is 410. The conversion efficiency from laser energy into the proton kinetic energy is up to 3%. This conversion efficiency is comparable or even higher than the results obtained with the same level laser ( J energy) interacts with the nano-meter level ultra thin target. In this paper we discuss on the comparison between our results and other experimental results obtained in other facilities.
Mima, Kunioki*; Azuma, Hirozumi*; Yamazaki, Akiyoshi; Kamiya, Tomihiro; Okuda, Chikaaki*; Ukyo, Yoshio*; Kato, Yoshiaki*; Gonzales, R.*; Soldo, F.*; Perlado, J. M.*; et al.
no journal, ,