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Iwasaki, Atsushi*; Sato, Takahiro*; Owada, Shigeki*; Togashi, Tadashi*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Kannari, Fumihiko*; Yagishita, Akira*; et al.
Reza Kenkyu, 40(9), p.687 - 690, 2012/09
no abstracts in English
Sato, Takahiro*; Iwasaki, Atsushi*; Ishibashi, Kazuki*; Okino, Tomoya*; Yamanouchi, Kaoru*; Adachi, Junichi*; Yagishita, Akira*; Yazawa, Hiroki*; Kannari, Fumihiko*; Aoyama, Makoto; et al.
Europhysics News, 42(5), P. 10, 2011/09
The resonant and non-resonant two-photon single ionization processes of He were investigated using intense free electron laser light in the extreme ultraviolet (XUV) region (53.4-61.4 nm) covering the 1s-2p and 1s-3p resonant transitions of He. On the basis of the dependences of the yield of He
on the XUV light-field intensity at 53.4, 58.4, 56.0 and 61.4 nm, the absolute values of the two-photon ionization cross sections of He at the four different wavelengths and their dependence on the light-field intensity were determined for the first time.
Sato, Takahiro*; Iwasaki, Atsushi*; Ishibashi, Kazuki*; Okino, Tomoya*; Yamanouchi, Kaoru*; Adachi, Junichi*; Yagishita, Akira*; Yazawa, Hiroki*; Kannari, Fumihiko*; Aoyama, Makoto; et al.
Journal of Physics B; Atomic, Molecular and Optical Physics, 44(16), p.161001_1 - 161001_5, 2011/08
Times Cited Count：39 Percentile：83.50(Optics)The resonant and non-resonant two-photon single ionization processes of He were investigated using intense free electron laser light in the extreme ultraviolet (XUV) region (53.4-61.4 nm) covering the 1s-2p and 1s-3p resonant transitions of He. On the basis of the dependences of the yield of He on the XUV light-field intensity at 53.4, 58.4, 56.0 and 61.4 nm, the absolute values of the two-photon ionization cross sections of He at the four different wavelengths and their dependence on the light-field intensity were determined for the first time.
Togashi, Tadashi*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Okino, Tomoya*; Yamanouchi, Kaoru*; et al.
Optics Express (Internet), 19(1), p.317 - 324, 2011/01
Times Cited Count：97 Percentile：95.92(Optics)The 13th harmonic of a Ti:sapphire (Ti:S) laser in the plateau region was injected as a seeding source to a 250-MeV free-electron-laser (FEL) amplifier. When the amplification conditions were fulfilled, strong enhancement of the radiation intensity by a factor of 650 was observed. The random and uncontrollable spikes, which appeared in the spectra of the Self-Amplified Spontaneous Emission (SASE) based FEL radiation without the seeding source, were found to be suppressed drastically to form to a narrow-band, single peak profile at 61.2 nm. The properties of the seeded FEL radiation were well reproduced by numerical simulations. We discuss the future precept of the seeded FEL scheme to the shorter wavelength region.
crystalAkahane, Yutaka; Aoyama, Makoto; Sugiyama, Akira; Kubo, Ryoichi; Ogawa, Kanade; Tsuji, Koichi; Yamakawa, Koichi
Optics Letters, 33(5), p.494 - 496, 2008/03
Times Cited Count：3 Percentile：19.44(Optics)A diode-pumped, cryogenically-cooled Yb:LuLiF regenerative amplifier has been developed for the first time to our knowledge. A chirped-seed pulse was amplified and compressed in the regenerative amplifier, simultaneously, which generated 
6-mJ, 13-ps pulses at 999 nm wavelength without a pulse compressor. Simultaneous lasing at 999 nm and 1024 nm, respectively, was demonstrated, which could be used for different frequency generation in the THz region.
Aoyama, Makoto; Akahane, Yutaka; Ogawa, Kanade; Tsuji, Koichi; Sugiyama, Akira; Harimoto, Tetsuo*; Kawanaka, Junji*; Nishioka, Hajime*; Fujita, Masayuki*; Yamakawa, Koichi
Reza Kenkyu, 35(6), p.398 - 399, 2007/06
We have demonstrated optical parametric chirped-pulse amplification by using a diode-pumped Yb:YLF CPA laser system as a pump source and achieved an ultra-broadband amplification of over 200-nm supporting a 12.6-fs duration (3.7 optical cycles) in spite of being operated around degeneracy. By using a two-stage OPCPA with a higher-energy pump pulse, it should be able to produce a terawatt-class, few-cycle laser pulse without complexly and enlarging the system size. Such a laser is useful for the generation of attosecond pulse generation in the xuv region as well as other high field applications.
Kato, Yoshiaki; Daido, Hiroyuki; Nagashima, Keisuke; Kawachi, Tetsuya; Hasegawa, Noboru; Tanaka, Momoko; Tang, H.; Tai, R.; Lu, P.; Kishimoto, Maki; et al.
AIP Conference Proceedings 641, p.31 - 39, 2002/00
no abstracts in English
Daido, Hiroyuki; Yamakawa, Koichi; Yamagiwa, Mitsuru; Arisawa, Takashi; Kato, Yoshiaki; Noda, Akira*; Uesaka, Mitsuru*; Ogata, Atsushi*; Matsukado, Koji*
Proceedings of 4th Symposium on Accelerator and Related Technology for Application, p.111 - 112, 2001/10
no abstracts in English
Abe, Tetsuya; Hiroki, Seiji; Tanzawa, Sadamitsu; Kosaku, Yasuo; Takauchi, Hisao*; Yamakawa, Akira*
JAERI-Research 2001-029, 13 Pages, 2001/05
JAERI-Research-2001-029.pdf:3.39MB
no abstracts in English
-ray emission source developmentArisawa, Takashi; Matoba, Toru; Yamakawa, Koichi; Maruyama, Yoichiro; Sasuga, Tsuneo; Wakaida, Ikuo; Nakajima, Kazuhisa*; Sasaki, Akira; Minehara, Eisuke; Oshima, Masumi
Proc. of the 1st International Induced Gamma Emision Workshop, p.29 - 41, 1999/00
no abstracts in English
Arisawa, Takashi; Matoba, Toru; Sasuga, Tsuneo; Nakajima, Kazuhisa*; Yamakawa, Koichi; Sasaki, Akira
Proc. of Int. Conf. on LASERS'96, p.1 - 12, 1996/00
no abstracts in English
Abe, Tetsuya; Murakami, Yoshio; ; ; Yamakawa, Akira*
JAERI-Research 94-023, 22 Pages, 1994/10
JAERI-Research-94-023.pdf:2.31MB
no abstracts in English
Aoyama, Makoto; Ogawa, Kanade*; Akahane, Yutaka; Tsuji, Koichi; Sugiyama, Akira; Kawanaka, Junji*; Nishioka, Hajime*; Fujita, Masayuki*; Yamakawa, Koichi
no journal, ,
no abstracts in English
Akahane, Yutaka; Aoyama, Makoto; Sugiyama, Akira; Kubo, Ryoichi; Tsuji, Koichi; Ogawa, Kanade; Yamakawa, Koichi
no journal, ,
We have developed a diode-pumped, cryogenically-cooled Yb:LuLiF regenerative amplifier, for the first time to our knowledge, which amplified 999 and 1024 nm chirped seed pulse to 6 and 8.5 mJ, respectively. Durations of amplified laser pulses in the regen were compressed to 13.2 ps and 27.4 ps in 999 and 1024 nm amplification, respectively, by gain-narrowing of chirped pulses, which enables us to apply output laser pulses to nonlinear applications directly without additional pulse compressor. We have also demonstrated simultaneous two-color lasing at 999 nm and 1024 nm, which could be used for different frequency generation in the THz region.
:LuLiF crystalAkahane, Yutaka; Aoyama, Makoto; Sugiyama, Akira; Kubo, Ryoichi*; Ogawa, Kanade; Tsuji, Koichi; Yamakawa, Koichi
no journal, ,
A diode-pumped regenerative amplification with cryogenically cooled Yb : LuLiF crystal has been demonstrated for the first time to our knowledge. A chirped-seed pulse was amplified and compressed in the regenerative amplifier, simultaneously, which generated 6 mJ, 13 ps pulses at 999 nm in wavelength and 8.5 mJ, 27 ps pulses at 1024 nm, respectively, without a pulse compressor. Simultaneous lasing at 999 and 1024 nm was demonstrated, which could be used for different frequency generation in the terahertz region.
:LuLiF crystalAkahane, Yutaka; Aoyama, Makoto; Sugiyama, Akira; Kubo, Ryoichi*; Ogawa, Kanade; Tsuji, Koichi; Yamakawa, Koichi
no journal, ,
We have performed chirped-pulse regenerative amplification at 999 nm and 1024 nm wavelengths with cryogenically-cooled Yb:LuLiF crystal. High-energy amplified pulses with energies of 6 mJ and 8.5 mJ were obtained at 999 nm and 1024nm wavelengths, respectively. In the regen durations of output pulses were compressed to 13 ps and 27 ps, respectively by gain-narrrwoing, so these pulses are available as pump sources for nonlinear effects without additional pulse compression devices. Simultaneous two-color lasing was also performed in this study, which is available for differential frequency generation in THz region.
Akahane, Yutaka; Aoyama, Makoto; Ogawa, Kanade; Tsuji, Koichi; Sugiyama, Akira; Yamakawa, Koichi; Kawanaka, Junji*; Harimoto, Tetsuo*; Nishioka, Hajime*; Fujita, Masayuki*
no journal, ,
We have confirmed ultra-broadband optical-parametric amplification (OPA) over 200 nm pumped by one beam of Yb:YLF CPA laser at degeneracy. A white light seed pulse with a bandwidth of 400 nm is generated by the 80-fs duration mode-locked pulse, that was identical to seed pulse for the Yb:YLF CPA pump laser, through a photonic crystal fiber, and then temporally stretched to -2 ps by passing through a glass block and injected to the BBO crystal at an internal crossing angle of 0.6 degree. The pump pulse with 3ps pulse duration was down-collimated and used to pump the crystal with an energy of 1.1 mJ. As a result, we have observed an ultra-broadband amplification over 200nm. The OPA gain was measured to be -10
, which corresponds to sub-100 
J energy of amplified signal pulse. With injecting second pump pulse with a different internal crossing angle of 1.2 degree, our OPCPA could amplify the 400 nm bandwidth which supports the intense few-cycle pulse generation.
Aoyama, Makoto; Akahane, Yutaka; Ogawa, Kanade; Tsuji, Koichi; Sugiyama, Akira; Yamakawa, Koichi; Harimoto, Tetsuo*; Kawanaka, Junji*; Nishioka, Hajime*; Fujita, Masayuki*
no journal, ,
no abstracts in English
Akahane, Yutaka; Aoyama, Makoto; Ogawa, Kanade; Tsuji, Koichi; Sugiyama, Akira; Harimoto, Tetsuo*; Kawanaka, Junji*; Nishioka, Hajime*; Fujita, Masayuki*; Yamakawa, Koichi
no journal, ,
We present an ultra-broadband intense optical-parametric chirped-pulse amplification system pumped by a cryogenically-cooled Yb:YLF chirped-pulse amplification laser.
Akahane, Yutaka; Aoyama, Makoto; Sugiyama, Akira; Kubo, Ryoichi; Ogawa, Kanade; Tsuji, Koichi; Yamakawa, Koichi
no journal, ,
A diode-pumped, cryogenically-cooled Yb:LuLiF
regenerative amplifier has been developed for the first time to our knowledge, which generated 6-mJ, 13-ps pulses at 999 nm wavelength without a pulse compressor.
:LuLiF crystalAkahane, Yutaka; Aoyama, Makoto; Kubo, Ryoichi; Sugiyama, Akira; Ogawa, Kanade; Tsuji, Koichi; Yamakawa, Koichi
no journal, ,
A diode-pumped, cryogenically-cooled Yb:LuLiF regenerative amplifier has been developed for the first time to our knowledge, which generated 6-mJ, 13-ps pulses at 999 nm wavelength without a pulse compressor.
