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Tanaka, Momoko; Ochi, Yoshihiro; Kosuge, Atsushi; Okada, Hajime; Mori, Michiaki; Kiriyama, Hiromitsu; Tsubouchi, Masaaki; Nagashima, Keisuke
JAEA-Conf 2014-001, p.32 - 33, 2014/09
We have constructed a high power kHz laser system using Yb:YAG thin-disk as a gain medium for a driver laser of THz wave generation. A 4-bounce regenerative amplifier is constructed and output energy up to 10 mJ is obtained. Using compressed pulse, we demonstrated THz wave generation with LiNbO
crystal.
Kiriyama, Hiromitsu; Mori, Michiaki; Suzuki, Masayuki*; Daito, Izuru*; Okada, Hajime; Ochi, Yoshihiro; Tanaka, Momoko; Sato, Masatoshi*; Tamaoki, Yoshinori*; Yoshii, Takehiro*; et al.
Reza Kenkyu, 42(6), p.441 - 447, 2014/06
We describe three specific high power laser systems that are being developed in our laboratory for many applications in high field science, nonlinear optics and material processing. We report on a femtosecond petawatt-class Ti:sapphire chirped-pulse amplification laser system that can produce a pulse energy of 20 J of 40 fs pulse duration, a picosecond high intensity Yb:YAG chirped-pulse amplification laser system that can generate a pulse energy of 100 mJ of 0.5 ps pulse duration, and a nanosecond high repetition rate Nd:YAG laser system that can provide an average power of 360 W with a pulse duration of 30 ns delivered at a 1 kHz repetition rate. We discuss the basic design aspects and present the results from our experimental investigations of these laser systems.
Ishino, Masahiko; Faenov, A.*; Tanaka, Momoko; Pikuz, T.; Tamotsu, Satoshi*; Hasegawa, Noboru; Nishikino, Masaharu; 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
Times Cited Count：0 Percentile：0
O/SiO multilayerOchi, Yoshihiro; Nagashima, Keisuke; Okada, Hajime; Tanaka, Momoko; Tateno, Ryo*; Furukawa, Yasuyuki*; Sugiyama, Akira
Proceedings of SPIE, Vol.8885, p.88851Z_1 - 88851Z_6, 2013/11
Times Cited Count：4 Percentile：87.97We designed and fabricated high damage-resistant AR coating using AlO/SiO layers. As a result of irradiation test using 500 ps pulses at 1 kHz, the damage threshold of the AR coating was estimated to be over 36 J/cm
(average value). We also fabricated high reflection (HR) mirrors using AlO/SiO layers added on TaO
/SiO layers and measured damage threshold of them for 7 ns, 500 ps, and 1 ps pulses.
Ishino, Masahiko; Faenov, A.*; Tanaka, Momoko; Tamotsu, Satoshi*; Pikuz, T.; Hasegawa, Noboru; Nishikino, Masaharu; Inogamov, N.*; Skobelev, I.*; Fortov, V.*; et al.
Proceedings of SPIE, Vol.8849, p.88490F_1 - 88490F_8, 2013/09
Times Cited Count：2 Percentile：74.29Nagashima, Keisuke; Kosuge, Atsushi; Ochi, Yoshihiro; Tanaka, Momoko
Optics Express (Internet), 21(16), p.18640 - 18645, 2013/07
Times Cited Count：13 Percentile：59.03(Optics)A novel method for increasing diffraction efficiency of transmission gratings is proposed. In this method, dielectric multilayers are inserted between a grating region and a substrate. These multilayers work as an anti-reflection coating for the transmission grating. It is presented that a grating with 1740 grooves/mm has the diffraction efficiency over 99% using this anti-reflection coating.
Magnitskiy, S.*; Nagorskiy, N.*; Faenov, A.*; Pikuz, T.; Tanaka, Momoko; Ishino, Masahiko; Nishikino, Masaharu; Fukuda, Yuji; Kando, Masaki; Kawachi, Tetsuya; et al.
Nature Communications (Internet), 4, p.1936_1 - 1936_7, 2013/06
Times Cited Count：5 Percentile：30.58(Multidisciplinary Sciences)Advent of plasma-based transient collisional excitation X-ray lasers allowed us to realize compact coherent X-ray sources, thus opening the way to a wide range of applications. Here we report the observation of unexpected concentric rings in the far-field beam profile at the output of a two-stage plasma-based X-ray laser developed in Japan Atomic Energy Agency, which can be considered as the first manifestation of a mirage phenomenon in X-rays. We have developed a method of solving the Maxwell-Bloch equations, which has allowed to find that the observed phenomenon is due to the emergence in the plasma-amplifier of X-ray mirage in the form of the phase matched coherent virtual point source. The obtained results bring a new insight into physical nature of amplification of X-ray radiation in laser-induced plasma amplifiers and open new opportunities for X-ray plasma diagnostics and extreme UV lithography.
thin film by oxidizing metallic titaniumYoshida, Fumiko; Tanaka, Momoko; Nagashima, Keisuke
Thin Solid Films, 537, p.23 - 27, 2013/06
Times Cited Count：2 Percentile：10.96(Materials Science, Multidisciplinary)Ishino, Masahiko; Faenov, A. Ya.*; Tanaka, Momoko; Tamotsu, Satoshi*; Hasegawa, Noboru; Nishikino, Masaharu; Pikuz, T.; Kaihori, Takeshi*; Kawachi, Tetsuya
Applied Physics A, 110(1), p.179 - 188, 2013/01
Times Cited Count：26 Percentile：73.28(Materials Science, Multidisciplinary)Ishino, Masahiko; Faenov, A.*; Tanaka, Momoko; Hasegawa, Noboru; Nishikino, Masaharu; Tamotsu, Satoshi*; Pikuz, S.*; Inogamov, N. A.*; Zhakhovsky, V. V.*; Skobelev, I.*; et al.
AIP Conference Proceedings 1465, p.236 - 240, 2012/07
Times Cited Count：2 Percentile：64.86We irradiated the focusing soft X-ray laser pulses having a wavelength of 13.9 nm and the duration of 7 ps to aluminum surface. After the irradiation process, the irradiated surface was observed with a scanning electron microscope. The surface modifications caused by soft X-ray laser single pulse exposure were clearly seen. In addition, it was found that the conical structures having around 100 nm in diameters were formed in the shallow features. The nano-meter size modified surface structures on aluminum induced by the soft X-ray laser pulse is interesting as the newly surface structure. Hence, the soft X-ray laser beam would be a candidate for a tool of micromachining. We also provide a thermomechanical modeling of the soft X-ray laser interaction with aluminum briefly to explain the surface modification.
Norman, G.*; Starikov, S.*; Stegailov, V.*; Fortov, V.*; Skobelev, I.*; Pikuz, T.; Faenov, A.*; Tamotsu, Satoshi*; Kato, Yoshiaki*; Ishino, Masahiko; et al.
Journal of Applied Physics, 112(1), p.013104_1 - 013104_8, 2012/07
Times Cited Count：41 Percentile：83.14(Physics, Applied)Ishino, Masahiko; Faenov, A. Y.*; Tanaka, Momoko; Hasegawa, Noboru; Nishikino, Masaharu; Tamotsu, Satoshi*; Pikuz, T.; Oba, Toshiyuki*; Kaihori, Takeshi; Kawachi, Tetsuya
Journal of Laser Micro/Nanoengineering, 7(2), p.147 - 151, 2012/05
Times Cited Count：5 Percentile：29.21(Nanoscience & Nanotechnology)We irradiated the soft X-ray laser (SXRL) pulses having a wavelength of 13.9 nm, the duration time of 7 ps to aluminum (Al), copper (Cu) and gold (Au) surfaces. After the irradiation processes of SXRL beam with laser flux of 
14 mJ/cm for Al case and of 21 mJ/cm for Cu and Au cases, the modified surfaces were observed with the visible microscope, the scanning electron microscope, and the atomic force microscope. The surface modifications caused by the SXRL irradiations were clearly seen on the surfaces, and it was found that the conical structures having around 100 nm in diameters were formed on the Al surface under a single pulse shot. The conical structures were formed in the features with the average depth of about 40 nm, and this value was in accordance with the attenuation length of the SXRL beam for Al. The modified structure on Al surface induced by SXRL pulse irradiations is different from those of Cu and Au surfaces. The modified structure formed on Al surface induced by the SXRL pulse exposure is interesting as the newly structure. Hence, the SXRL beam would be a candidate for a tool of micromachining, which enable to fabricate of three dimensional structures with nano-meter size on Al surface.
imaging device of high spatial resolution ZnO scintillatorNakazato, Tomoharu*; Shimizu, Toshihiko*; Yamanoi, Kohei*; Sakai, Kohei*; Takeda, Kohei*; Nishi, Ryosuke*; Minami, Yuki*; Cadatal-Raduban, M.*; Sarukura, Nobuhiko*; Nishimura, Hiroaki*; et al.
Japanese Journal of Applied Physics, 50(12), p.122202_1 - 122202_4, 2011/12
Times Cited Count：9 Percentile：39.26(Physics, Applied)We demonstrate the potential of a hydrothermal method-grown ZnO as a high-spatial resolution imaging device for in-situ soft X-ray laser diagnostics by characterizing the exciton emission patterns. By plotting the emission pattern radii at each position, we estimated the evolution of the beam radius around the focal point. The beam profile of the Ni-like Ag ion plasma laser was estimated from the waist radii as 29 and 21
m, the divergence angle as 7.2 and 11 mrad and the M2 factor as 47 and 50 in the horizontal- and vertical-axis, respectively. Spatial resolution of the magnifier was estimated to be 6m and is expected to improve by optimizing the optics of the magnifier and using a telescope. Our results would enhance the use of ZnO as an imaging device that would play a crucial role in the development and application of soft X-ray light sources.
Kawachi, Tetsuya; Hasegawa, Noboru; Nishikino, Masaharu; Ishino, Masahiko; Imazono, Takashi; Oba, Toshiyuki; Kaihori, Takeshi; Kishimoto, Maki; Ochi, Yoshihiro; Tanaka, Momoko; et al.
X-Ray Lasers 2010; Springer Proceedings in Physics, Vol.136, p.15 - 24, 2011/12
This paper reviews recent improvement in the source development of laser-driven X-ray lasers and the applications in the research fields of material science, laser processing, X-ray imaging, and radiation damage in biological cells. In the application for material science, we have firstly observed temporal correlation between the domain structures of ferro-electric substance under the Curie temperature. In the laser processing, new X-ray laser interferometer reveals us the nano-scale surface distortion of substance pumped by a femto-second optical pulse. In the X-ray diffraction image, we have taken several static images of micro-structure of samples: now we are trying to extend the objective to nano-scale dynamics using pump and probe method. In the radiation damage of biological cells, we observed double strand break in DNA using X-ray laser exposure; this results are compared with the case using incoherent several KeV X-ray exposure.
Hasegawa, Noboru; Ochi, Yoshihiro; Kawachi, Tetsuya; Terakawa, Kota*; Tomita, Takuro*; Yamamoto, Minoru; Nishikino, Masaharu; Oba, Toshiyuki; Kaihori, Takeshi; Imazono, Takashi; et al.
X-Ray Lasers 2010; Springer Proceedings in Physics, Vol.136, p.353 - 358, 2011/12
The understanding of the dynamics of the initial process is important for the micro processing and welding by the ultra-short laser pulse. The X-ray laser is suitable for probing this initial process because it has short wavelength (Ni-like Ag, 13.9 nm) and short duration (7 ps). For this investigation, the origin of time of the pumping pulse is quite important. In this study, we used the scintillation plate and the plasma gate technique to realize the spatial and temporal synchronization of the pump and probe pulses. For the spatial alignment, a CsI scintillation plate that was set at the sample position was illuminated by both the X-ray laser pulse, and the fluorescence light were detected by the CCD camera. For the temporal synchronization, we set a thin foil at the sample position. We measured the transmission of the X-ray laser while changing a temporal delay of the pumping laser with respect to the time of X-ray laser pulse to obtain the origin of the irradiation time.
Inogamov, N. A.*; Anisimov, S. I.*; Petrov, Y. V.*; Khokhlov, V. A.*; Zhakhovskii, V. V.*; Faenov, A. Ya.*; Pikuz, T.; Fortov, V. E.*; Skobelev, I. Y.*; Kato, Yoshiaki*; et al.
Journal of Optical Technology, 78(8), p.473 - 480, 2011/08
Times Cited Count：5 Percentile：29.56(Optics)Starikov, S. V.*; Stegailov, V. V.*; Norman, G. E.*; Fortov, V. E.*; Ishino, Masahiko; Tanaka, Momoko; Hasegawa, Noboru; Nishikino, Masaharu; Oba, Toshiyuki*; Kaihori, Takeshi; et al.
JETP Letters, 93(11), p.642 - 647, 2011/04
Times Cited Count：24 Percentile：75.71(Physics, Multidisciplinary)Sugiyama, Akira; Kiriyama, Hiromitsu; Ochi, Yoshihiro; Mori, Michiaki; Tanaka, Momoko; Sasao, Fumitaka; Kosuge, Atsushi; Okada, Hajime
JAEA-Conf 2011-001, p.15 - 18, 2011/03
Main theme of our group in this middle term JAEA program is a development of high-averaged power short pulse laser system pumped by LDs (laser diodes). To realize this next term laser system, we have just started considering a Yb doped ceramics laser with a several members of KPSI. We have also developed a laser system named QUADRA (high-Quality Ultra ADvanced RAdiation Sources) in C-Phost program. In the first term up to FYH22, essential studies for QUADRA have been investigated. In the second term, QUADRA development will be merged with the next term laser system in JAEA to produce high powered THz radiation. In addition to these developments, we support to improve the performances of conventional high-power laser system, J-KAREN, for the requirement of advanced application studies in this middle term JAEA program.
Tanaka, Momoko; Nakazato, Tomoharu*; Shimizu, Toshihiko*; Yamanoi, Kohei*; Sakai, Kohei*; Sarukura, Nobuhiko*; Nishikino, Masaharu; Oba, Toshiyuki; Kaihori, Takeshi; Ochi, Yoshihiro; et al.
JAEA-Conf 2011-001, p.126 - 128, 2011/03
The spatial resolution of hydrothermal method grown zinc oxide (ZnO) scintillator was evaluated using X-ray laser focused with Fresnel zone plate. The fluorescence image of the ZnO scintillator was measured to be less than 10um using CCD camera coupled with a Schbartzchild expander mirror. The availability of large size ZnO crystal up to 3-inch is quite attractive for future lithography and imaging applications.
Sarukura, Nobuhiko*; Nakazato, Tomoharu*; Shimizu, Toshihiko*; Yamanoi, Kohei*; Sakai, Kohei*; Ehrentraut, D.*; Fukuda, Tsuguo*; Tanaka, Momoko; Nishikino, Masaharu; Kawachi, Tetsuya
Reza Kenkyu, 39(3), p.193 - 196, 2011/03
Development of light sources in the soft X-ray/X-ray region, such as laser induced plasma emission and XFEL, is in demand for applications in various fields of science, medicine, and industry, among others. To promote this endeavor, development of imaging devices as diagnostic tools in this wavelength region is required. ZnO is a prominent candidate material for high spatial and temporal resolution imaging devices because of its emission at 380 nm, lifetime of less than 1 ns, and availability of large and cheap but high quality crystals. We obtained a single shot image of ZnO emission pattern excited by an X-ray laser at the Advanced Photon Research Center, Japan Atomic Energy Agency. The spatial resolution was estimated to be around 10 m. This result shows that ZnO can be used as a powerful imaging device for applications such as EUV lithography.
