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Yamakawa, Koichi; Akahane, Yutaka; Ogawa, Kanade; Aoyama, Makoto
Denki Gakkai Hikari, Ryoshi Debaisu Kenkyukai Shiryo OQD-09-61, p.13 - 16, 2009/09
We have proposed and demonstrated a novel optical-parametric chirped-pulse amplification scheme in which an even order dispersion of an idler pulse is compensated by passing through an identical positive dispersive material used for temporal stretching a signal pulse. By compressing the idler pulses having a negatively chirp in this manner, high power sub-100 fs pulses were successfully obtained with only a transparent glass block used for the stretcher and compressor. A feasible design of real world femtosecond laser systems employing this scheme is also discussed.
Yoshigoe, Akitaka; Teraoka, Yuden
Denki Gakkai Hikari, Ryoshi Debaisu Kenkyukai Shiryo OQD-09-56, p.67 - 70, 2009/05
To clarify the mechanisms of the oxidation of Si(111)-7
7 surface at 300 K, the time evolution of oxygen bonding configurations and silicon oxidation states has been observed by real-time photoelectron spectroscopy using synchrotron radiation. In the initial stages of oxidation, it is found that oxygen molecule from gas phase dissociatively chemisorbs into the Si-Si backbond sites of the Si adatom on Si(111)-77 surface. We also clarify that the structure of the well-known molecularly-chemisorbed oxygen is a 
oxygen in the 
structure.
Koike, Masato; Imazono, Takashi; Kawazoe, Tadashi*; Otsu, Motoichi*; Sano, Kazuo*
Denki Gakkai Hikari, Ryoshi Debaisu Kenkyukai Shiryo OQD-08-34, p.15 - 18, 2008/05
A Mo/SiO
multilayer laminar-type holographic grating having an average groove density of 2400 lines/mm is designed and fabricated for use with a soft X-ray flat field spectrograph. A varied-line-spaced grooves pattern is generated by the use of an aspheric wavefront recording system and laminar-type grooves are formed by a reactive ion-etching method. The measured first-order diffraction efficiency is 18
20%. The flat field spectrograph equipped with the grating indicates a spectral line width of 814 eV for the emission spectra generated from electron-impact X-ray sources. A Mo/SiO multilayer grating having a groove density of 7600 lines/mm fabricated by use of a new lithography machine based on optical near field technologies showed first-order diffraction efficiency of 3%. It is over one order magnitude higher than that of the other orders.
Yamakawa, Koichi
Denki Gakkai Hikari, Ryoshi Debaisu Kenkyukai Shiryo OQD-04-46, p.27 - 35, 2004/11
no abstracts in English
Sugiyama, Akira; Fukuyama, Hiroyasu*; Katsurayama, Masamichi*; Anzai, Yutaka*
Denki Gakkai Hikari, Ryoshi Debaisu Kenkyukai OQD-00-50, p.23 - 28, 2000/10
no abstracts in English
Yamakawa, Koichi*
OQD-96-14, 0, p.29 - 38, 1996/03
no abstracts in English
Akahane, Yutaka; Ogawa, Kanade; Yamakawa, Koichi
no journal, ,
We have proposed and demonstrated pulse compression of an idler pulse on ultrafast optical-parametric chirped-pulse amplification with an identical glass-block used for signal pulse stretcher. This scheme is useful for constructing robust intense femtosecond laser for industry.
Kado, Masataka; Kishimoto, Maki; Tamotsu, Satoshi*; Yasuda, Keiko*; Aoyama, Masato*; Tone, Shigenobu*; Shinohara, Kunio*
no journal, ,
Laser-plasma soft X-ray sources have advantage of brightness and short pulse duration and a soft X-ray microscope using them can observe live biological cells with a high spatial resolution. We have succeeded to observe fine structures of cellular organelles of live biological cells and also structural deformations of apoptotic nuclei.
Yamada, Taichi; Kawabata, Kuniaki
no journal, ,
In reactor buildings of Fukushima Daiichi Nuclear Power Plant (hereinafter referred as 1F), there are still many of uninvestigated areas due to the accident on March 11th, 2011. Because it is easy to assume that these uninvestigated areas are high radiation, remote control robots is used for investigations in reactor buildings. Thus, robot mapping technology called SLAM (Simultaneous Localization And Mapping) is one of the key technology for the decommissioning. This research aimed to construct the sensor database aimed to enhance SLAM research.