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Ogawa, Kanade; Aoyama, Makoto; Akahane, Yutaka; Tsuji, Koichi; Kawanaka, Junji*; Harimoto, Tetsuo*; Nishioka, Hajime*; Fujita, Masayuki*; Yamakawa, Koichi
Japanese Journal of Applied Physics, 47(6), p.4592 - 4594, 2008/06
Times Cited Count：8 Percentile：31.84(Physics, Applied)We have demonstrated ultra-broadband optical parametric chirped-pulse amplification of more than 350 nm bandwidth in a near infrared region. We have observed a substantial enhancement (nearly 2-fold) of the parametric amplification bandwidth by using time delayed two broadband pump pulses at degeneracy.
Ogawa, Kanade; Akahane, Yutaka; Harimoto, Tetsuo*; Aoyama, Makoto; Tsuji, Koichi; Kawanaka, Junji*; Nishioka, Hajime*; Fujita, Masayuki*; Yamakawa, Koichi
Reza Kenkyu, 35(9), p.596 - 598, 2007/09
no abstracts in English
)
chirped-pulse regenerative amplifierOgawa, Kanade; Akahane, Yutaka; Aoyama, Makoto; Tsuji, Koichi; Tokita, Shigeki*; Kawanaka, Junji*; Nishioka, Hajime*; Yamakawa, Koichi
Optics Express (Internet), 15(14), p.8598 - 8602, 2007/07
Times Cited Count：23 Percentile：69.06(Optics)Ytterbium (Yb
) doped gain media are one of promising laser materials for the next generation of diode-pumped high-power lasers. Yb-doped media have several advantages. It has wide absorption bandwidth, the low quantum defect, and the simple electronic structure. Yb:KY(WO) (Yb:KYW) and Yb:KG(WO) (Yb:KGW) have a large absorption and wide emission cross section, broad emission spectral range, and high thermal conductivity, yielding a high repetition-rate, high-energy, sub-picosecond pulses. However, multi-millijoule-class Yb:KYW or Yb:KGW lasers have not yet been reported so far, excepting a massive, joule-class Ti:sapphire laser pumped Yb:KGW regenerative amplifier. So, We developed a compact diode-pumped, cryogenically-cooled chirped-pulse Yb:KYW regenerative amplifier. An amplified pulse with an energy of 5.5 mJ and a high optical conversion efficiency of 
14% is achieved. Regenerative pulse shaping is also used to counter gain narrowing during amplification.
Akahane, Yutaka; Aoyama, Makoto; Ogawa, Kanade; Tsuji, Koichi; Tokita, Shigeki*; Kawanaka, Junji*; Nishioka, Hajime*; Yamakawa, Koichi
Optics Letters, 32(13), p.1899 - 1901, 2007/07
Times Cited Count：42 Percentile：83.50(Optics)A diode-pumped, cryogenic-cooled Yb:YAG regenerative amplifier utilizing gain-narrowing has been developed. A 1.2-ns chirped-seed pulse was amplified and compressed in the regenerative amplifier, simultaneously, which generated a 35-ps pulse with 8-mJ of energy without a pulse compressor. Second-harmonics of the amplified pulse was used to pump picosecond two-color optical parametric amplification.
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.
Nishioka, Hajime*; Kawanaka, Junji
Hikari Araiansu, 14(11), p.21 - 25, 2003/11
no abstracts in English
Kawanaka, Junji; Yamakawa, Koichi; Nishioka, Hajime*; Ueda, Kenichi*
Optics Letters, 28(21), p.2121 - 2123, 2003/11
Times Cited Count：90 Percentile：93.56(Optics)no abstracts in English
crystal at low temperatureKawanaka, Junji; Yamakawa, Koichi; Nishioka, Hajime*; Ueda, Kenichi*
Optics Express (Internet), 10(10), p.455 - 460, 2002/05
Times Cited Count：48 Percentile：83.94(Optics)no abstracts in English
Kawanaka, Junji; Yamakawa, Koichi; Nishioka, Hajime*; Ueda, Kenichi*
Proceedings of Conference on Lasers and Electro-Optics / Quantum Electronics and Laser Science Conference (CLEO/QELS 2002), p.CPDC8_1 - CPDC8_3, 2002/00
no abstracts in English
Kawanaka, Junji; Nishioka, Hajime*; Inoue, Norihiro*; Ueda, Kenichi*
Applied Optics, 40(21), p.3542 - 3546, 2001/07
Times Cited Count：57 Percentile：88.82(Optics)no abstracts in English
Kawanaka, Junji; Nishioka, Hajime*; Inoue, Norihiro*; Kubota, Yoshinori*; Ueda, Kenichi*
XIII International Symposium on Gas Flow and Chemical Lasers and High-Power Laser Conference (Proceedings of SPIE Vol.4184) (CD-ROM), 4 Pages, 2000/09
no abstracts in English
Akahane, Yutaka; Aoyama, Makoto; Ogawa, Kanade; Tsuji, Koichi; Tokita, Shigeki*; Kawanaka, Junji*; Nishioka, Hajime*; Yamakawa, Koichi
no journal, ,
no abstracts in English
Akahane, Yutaka; Aoyama, Makoto; Ogawa, Kanade; Tsuji, Koichi; Tokita, Shigeki*; Kawanaka, Junji*; Nishioka, Hajime*; Yamakawa, Koichi
no journal, ,
A diode-pumped Yb:YAG regenerative amplifier utilizing gain-narrowing has been developed. A chirped-seed pulse was amplified and compressed in the regenerative amplifier, simultaneously, which generated the picosecond pulses with 8 mJ of energy without a pulse compressor.
) chirped-pulse regenerative amplifierAoyama, Makoto; Ogawa, Kanade; Akahane, Yutaka; Tsuji, Koichi; Tokita, Shigeki*; Kawanaka, Junji*; Nishioka, Hajime*; Yamakawa, Koichi
no journal, ,
no abstracts in English
edges on the Heusler alloy CoMnSiFujiwara, Hidenori*; Kogo, Junya*; Kasahara, Rika*; Nishioka, Takuma*; Fujimoto, Nao*; Nagai, Kodai*; Sekiyama, Akira*; Sumida, Kazuki; Takeda, Yukiharu; Saito, Yuji; et al.
no journal, ,
no abstracts in English
Suzuki, Takashi; Otosaka, Shigeyoshi*; Kuwabara, Jun; Nishioka, Jun*
no journal, ,
I concentrations in seawater from the Japan Sea and the Bering Sea were measured to evaluate its applicability as an oceanographic tracer. Surface seawater concentrations of I in the Japan Sea were higher than those in the Bering Sea, likely reflecting atmospheric transport patterns of I. Vertical profiles showed decreasing concentrations with depth, and in the Japan Sea, anthropogenic I was observed to reach bottom waters. The total inventory was higher in the Japan Sea, which is attributed to its unique circulation structure and topographic constraints. Furthermore, the turnover time of Japan Sea Bottom Water was estimated to be 200-520 years, demonstrating its usefulness as a tracer for ocean circulation.
Aoyama, Makoto; Akahane, Yutaka; Tsuji, Koichi; Ogawa, Kanade; Harimoto, Tetsuo*; Kawanaka, Junji*; Nishioka, Hajime*; Fujita, Masayuki*; Yamakawa, Koichi
no journal, ,
no abstracts in English
Akahane, Yutaka; Aoyama, Makoto; Ogawa, Kanade; Tsuji, Koichi; Harimoto, Tetsuo*; Kawanaka, Junji*; Nishioka, Hajime*; Fujita, Masayuki*; Yamakawa, Koichi
no journal, ,
no abstracts in English
Akahane, Yutaka; Aoyama, Makoto; Ogawa, Kanade; Tsuji, Koichi; Tokita, Shigeki*; Kawanaka, Junji*; Nishioka, Hajime*; Yamakawa, Koichi
no journal, ,
We have developed a diode-pumped, cryogenic-cooled Yb:YAG regenerative amplifier employing gain-narrowing. In the regenerative amplifier, a seed chirped-pulse was not only amplified but also temporally compressed, which generated the picosecond output pulses with 8-mJ of energy without a pulse compressor.
Yamakawa, Koichi; Aoyama, Makoto; Akahane, Yutaka; Tsuji, Koichi; Ogawa, Kanade; Harimoto, Tetsuo*; Kawanaka, Junji*; Nishioka, Hajime*; Fujita, Masayuki*
no journal, ,
We have demonstrated ultra-broadband optical parametric chirped-pulse amplification of 300-nm bandwidth pumped by a diode-pumped, cryogenic-cooled Yb:YLF chirped-pulse amplification laser.
