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Journal Articles

Intensity correlation measurement system by picosecond single shot soft X-ray laser

Kishimoto, Maki; Namikawa, Kazumichi*; Sukegawa, Kota*; Yamatani, Hiroshi*; Hasegawa, Noboru; Tanaka, Momoko

Review of Scientific Instruments, 81(1), p.013905_1 - 013905_5, 2010/01

AA2009-0790.pdf:0.78MB

 Times Cited Count:3 Percentile:19.15(Instruments & Instrumentation)

We developed a new soft X-ray speckle intensity correlation spectroscopy system by use of a single shot high brilliant plasma soft X-ray laser. The plasma soft X-ray laser is characterized by several picoseconds in pulse width, more than 90% special coherence, and 10$$^{11}$$ soft X-ray photons within a single pulse. We developed a Michelson type delay pulse generator using a soft X-ray beam splitter to measure the intensity correlation of X-ray speckles from materials and succeeded in generating double coherent X-ray pulses with picosecond delay times. Moreover, we employed a high-speed soft X-ray streak camera for the picosecond time-resolved measurement of X-ray speckles. We performed the X-ray speckle intensity correlation measurements for probing the relaxation phenomena of polarizations in polarization clusters in the paraelectric phase of the ferroelectric material BaTiO$$_{3}$$ near its Curie temperature and verified its performance.

Journal Articles

Frequency filter of seed X-ray by use of X-ray laser medium; Toward the generation of the temporally coherent X-ray laser

Hasegawa, Noboru; Kawachi, Tetsuya; Kishimoto, Maki; Sukegawa, Kota*; Tanaka, Momoko; Tai, R. Z.*; Ochi, Yoshihiro; Nishikino, Masaharu; Nagashima, Keisuke; Kato, Yoshiaki*

Japanese Journal of Applied Physics, 48(1), p.012503_1 - 012503_6, 2009/01

 Times Cited Count:6 Percentile:27.56(Physics, Applied)

We evaluate the characteristics of a higher-order harmonics light as a seed X-ray amplified through the laser-produced X-ray amplifier. Narrow spectral bandwidth of the X-ray amplifier works as the frequency filter of the seed X-ray, resulting in that only the temporally coherent X-ray is amplified. Experimental investigation using the 29th-order harmonic light of the Ti:sapphire laser at a wavelength of 26.9 nm together with the neon-like manganese X-ray laser medium shows obvious spectral narrowing of the seed X-ray and amplification without serious diffraction effects on the propagation of the amplified X-ray beam. This implies that the present combination is potential to realize temporally coherent X-ray lasers, with the expected duration of several 100 fs.

Journal Articles

Characterization of a high-brilliance soft X-ray laser at 13.9 nm by use of an oscillator-amplifier configuration

Nishikino, Masaharu; Hasegawa, Noboru; Kawachi, Tetsuya; Yamatani, Hiroshi; Sukegawa, Kota; Nagashima, Keisuke

Applied Optics, 47(8), p.1129 - 1134, 2008/03

 Times Cited Count:43 Percentile:87.23(Optics)

Journal Articles

Direct measurement of the temporal profile of the amplification gain of the transient collisional excitation neonlike manganese X-ray laser medium

Hasegawa, Noboru; Kawachi, Tetsuya; Sasaki, Akira; Kishimoto, Maki; Sukegawa, Kota; Tanaka, Momoko; Tai, R. Z.*; Ochi, Yoshihiro; Nishikino, Masaharu; Nagashima, Keisuke; et al.

Physical Review A, 76(4), p.043805_1 - 043805_5, 2007/10

 Times Cited Count:20 Percentile:68.27(Optics)

We firstly demonstrated the measurement of temporal profile of the amplification gain of the transient collisional excitation (TCE) X-ray laser with the solid target by use of X-ray diagnostic beam injection technique. In this experiment, higher-order harmonic light at a wavelength of 26.9 nm was injected into the neon-like manganese plasma as X-ray laser medium, and the amplified signal was observed. The obtained buildup time of the amplification gain was 23 ps measured from the time of the main pumping laser pulse, and the lifetime of the amplification gain was 27 ps. This result was in good agreement with the theoretical simulation by using an atomic kinetics code.

Journal Articles

Enhancement of double auger decay probability in xenon clusters irradiated with a soft-X-ray laser pulse

Namba, Shinichi*; Hasegawa, Noboru; Nishikino, Masaharu; Kawachi, Tetsuya; Kishimoto, Maki; Sukegawa, Kota; Tanaka, Momoko; Ochi, Yoshihiro; Takiyama, Ken*; Nagashima, Keisuke

Physical Review Letters, 99(4), p.043004_1 - 043004_4, 2007/07

 Times Cited Count:31 Percentile:78.29(Physics, Multidisciplinary)

The interaction of large Xe clusters with a soft X-ray laser pulse having a wavelength of 13.9 nm and an intensity of up to 2$$times$$10$$^{10}$$W/cm$$^{2}$$ was investigated using a time-of-flight ion mass spectrometer. It was found that Xe$$^{3+}$$ ions (which result from double Auger decay of 4d vacancies) became the dominant final ionic product with increasing cluster size and X-ray intensity. This is in contrast to the results of synchrotron radiation experiments involving free Xe atoms, in which Xe$$^{2+}$$ is the dominant resultant ion species. Possible mechanisms responsible for the enhancement of the double Auger transition probability in X-ray laser and cluster interaction are discussed.

JAEA Reports

Development of the high stability target system for double-target X-ray laser

Sukegawa, Kota*; Kishimoto, Maki; Kado, Masataka

JAERI-Tech 2004-077, 21 Pages, 2005/01

JAERI-Tech-2004-077.pdf:4.17MB

no abstracts in English

JAEA Reports

Design of chirp-pulse amplification laser system and test results of key elements for high-repetition rate soft X-ray lasers

Ochi, Yoshihiro; Hasegawa, Noboru; Suzuki, Yoji; Sukegawa, Kota*; Kawachi, Tetsuya; Kishimoto, Maki; Nagashima, Keisuke

JAERI-Tech 2004-062, 32 Pages, 2004/11

JAERI-Tech-2004-062.pdf:1.84MB

We have designed new chirp-pulse amplification (CPA) laser system for 0.1 Hz repetition rate soft X-ray laser system. We adopted the optical parametric chirped pulse amplifier (OPCPA) for a pre-amplifier because of its pulse controllability. For a main-amplifier, we decided to use a zigzag-slab amplifier because of its thermal radiation ability. In order to avoid the inhomogeneous spatial profile of the amplified laser beam, the image of the incident laser light created by a serrated aperture is transferred by use of an image relay system. In this report, we will show the preliminary test of each amplifier using a prototype system and the details of the final system design.

Journal Articles

Demonstration of a fully spatial coherent X-ray laser at 13.9 nm

Nishikino, Masaharu; Tanaka, Momoko; Ochi, Yoshihiro; Kishimoto, Maki; Ishino, Masahiko; Hasegawa, Noboru; Kado, Masataka; Sukegawa, Kota*; Kawachi, Tetsuya; Nagashima, Keisuke

IEEE Journal of Selected Topics in Quantum Electronics, 10(6), p.1382 - 1387, 2004/11

 Times Cited Count:9 Percentile:46.5(Engineering, Electrical & Electronic)

no abstracts in English

Journal Articles

Development of a full spatial coherent X-ray laser at 13.9 nm and its applications

Nagashima, Keisuke; Tanaka, Momoko; Nishikino, Masaharu; Kishimoto, Maki; Kado, Masataka; Kawachi, Tetsuya; Hasegawa, Noboru; Ochi, Yoshihiro; Sukegawa, Kota*; Tai, R.; et al.

Applied Physics B, 78(7), p.927 - 932, 2004/05

We have succeeded in developing a laser-pumped X-ray laser with full spatial coherence at 13.9 nm. A highly directed X-ray laser beam with the divergence of 0.2 mrad was generated from the double target experiment, where a seeding light from the first laser medium was amplified in the second medium. The observed divergence is close to the diffraction limit value within a factor of two. The seeding light was amplified in the second medium without refraction influence and the gain coefficient was about 8 cm-1. From the measurement of visibility, it was found that the spatial coherent length is longer than the beam diameter. As an application of this coherent X-ray laser, we observed a surface microstructure of ferroelectric material, BaTiO$$_{3}$$ and clarified a change of the microstructure near the Curie temperature.

Journal Articles

High-precision measurement of the wavelength of a nickel-like silver X-ray laser

Hasegawa, Noboru; Kawachi, Tetsuya; Utsumi, Takayuki*; Sasaki, Akira; Tanaka, Momoko; Kado, Masataka; Sukegawa, Kota*; Lu, P.; Kishimoto, Maki; Tai, R.; et al.

Japanese Journal of Applied Physics, Part 1, 43(5A), p.2519 - 2522, 2004/05

 Times Cited Count:12 Percentile:46.04(Physics, Applied)

We conducted high-precision measurements of the wavelength of the nickel-like silver X-ray laser in order to compare it with a theoretical wavelength. The reasons for using this laser are as follows: First, this laser line is in the wavelength region of Mo/Si multi-layer mirrors; therefore, this laser line is important for applications. Second, the strongamplification of this laser line has been obtained in our previous work, and the higher order line in the spectra obtained by our spectrometer can be used. Third, since silver is arelatively low-z material (z = 47), this wavelength is a ideal benchmark of atomic structural codes such as the Multiconfiguration Dirac-Fock (MCDF) code. The wavelength of the nickel-like silver X-ray laser was determined to be 13.887 nm. The comparison with MCDF codes shows that the present experimental result can work as a good benchmark of the accuracy of the codes.

Journal Articles

Development of a laser-pumped X-ray laser with full spatial coherence

Nagashima, Keisuke; Tanaka, Momoko; Nishikino, Masaharu; Kishimoto, Maki; Kado, Masataka; Kawachi, Tetsuya; Hasegawa, Noboru; Ochi, Yoshihiro; Sukegawa, Kota*; Tai, R.

Purazuma, Kaku Yugo Gakkai-Shi, 80(3), p.236 - 240, 2004/03

A laser-pumped X-ray laser with full spatial coherence has been developed for the first time. This X-ray laser has the wavelength of 13.9 nm and the beam divergence of 0.2 mrad. In the experiment, a seeding light from the first laser medium was amplified in the second medium, which worked as an active spatial filter. The observed beam divergence was close to the diffraction limited value within a factor of two. The seeding light was amplified in the second medium without refraction influence. The gain region of the second medium was far away from the target surface compared with that of the first medium and located in the considerably low density region. From the measurement of visibility, it was found that the spatial coherent length is longer than the beam diameter. It means that this X-ray laser beam is full spatial coherent.

Journal Articles

Demonstration of a soft-X-ray laser at 13.9 nm with full spatial coherence

Nishikino, Masaharu; Tanaka, Momoko; Nagashima, Keisuke; Kishimoto, Maki; Kado, Masataka; Kawachi, Tetsuya; Sukegawa, Kota*; Ochi, Yoshihiro; Hasegawa, Noboru; Kato, Yoshiaki

Physical Review A, 68(6), p.061802_1 - 061802_4, 2003/12

 Times Cited Count:60 Percentile:89.82(Optics)

We demonstrate a generation of highly coherent X-ray laser at 13.9 nm by oscillator-amplifier configuration with two targets. In the oscillator-amplifier configuration, the seeding X-ray laser beam from the first target is injected into the plasma amplifier at the second target. When the X-ray laser beam is not affected by refraction during propagation in the amplifier, the X-ray laser beam with small divergence and high coherence is generated. The observed X-ray laser beam has 0.2 mrad of the diffraction limited divergence and the full spatial coherence.

Journal Articles

Study of the anisotropy of electron energy distribution of optical-field ionized oxygen plasma by using polarization spectroscopy

Kim, J.*; Kim, D. E.*; Kawachi, Tetsuya; Hasegawa, Noboru; Sukegawa, Kota*; Iwamae, Atsushi*; Fujimoto, Takashi*

Journal of the Optical Society of Korea, 7(3), p.145 - 149, 2003/09

The anistropy of electron energy distribution in oxygen plasmas produced by a high intensinty laser was investigated by using polarization spectroscopy. An ultra-short pulsed laser with a pulse duration of 66.5 fs and a power density of 1$$times$$10$$^{17}$$ W/cm$$^{2}$$ was used. At this power density and pulse duration, the plasma was generated predominantly by optical field ionization. The degree of polarization of OVI 1s$$^{2}$$2p $$^{2}$$P$$^{2}$$-1s$$^{2}$$4d $$^{2}$$D$$^{0}$$ (J=1/2-3/2 and J=3/2-5/2) transition line at 129.92 $AA  was mesured. OVI $の1s$$^{2}$$ 2p$$^{2}$$P$$^{2}$$-1s$$^{2}$$4s$$^{2}$$S$$^{2}$$ (J=1/2-1/2 and J=3/2-1/2) transition line at 132.26 AA was used to calibrate the sensitivity of the optical system. The dependencies of the degree of polarization on the initial gas density and on the laser polarization were investigated. When the laser polarization was changed from a linear to a circlar polarization was decreased. When the initial gas density was increased, the degree of polarization was decreased.

Journal Articles

Development of a pumping laser system for X-ray laser research

Kawachi, Tetsuya; Kado, Masataka; Tanaka, Momoko; Hasegawa, Noboru; Nagashima, Keisuke; Sukegawa, Kota*; Lu, P.; Takahashi, Kenjiro; Namba, Shinichi; Koike, Masato; et al.

Applied Optics, 42(12), p.2198 - 2205, 2003/04

 Times Cited Count:27 Percentile:73.19(Optics)

no abstracts in English

Journal Articles

Spatial coherence measurement of the 13.9nm Ni-like Ag soft X-ray laser pumped by a 1.5ps, 20J laser

Tang, H.; Daido, Hiroyuki; Kishimoto, Maki; Sukegawa, Kota*; Tai, R.; Mesesson, S.*; Tanaka, Momoko; Lu, P.; Kawachi, Tetsuya; Nagashima, Keisuke; et al.

Japanese Journal of Applied Physics, 42(2A), p.443 - 448, 2003/02

 Times Cited Count:14 Percentile:51.25(Physics, Applied)

no abstracts in English

Journal Articles

Picosecond snapshot of the speckles from ferroelectric BaTiO$$_{3}$$ by means of X-ray lasers

Tai, R.; Namikawa, Kazumichi*; Kishimoto, Maki; Tanaka, Momoko; Sukegawa, Kota*; Hasegawa, Noboru; Kawachi, Tetsuya; Kado, Masataka; Lu, P.; Nagashima, Keisuke; et al.

Physical Review Letters, 89(25), p.257602_1 - 267602_4, 2002/12

 Times Cited Count:38 Percentile:81.01(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Demonstration of a transient-gain nickel-like xenon-ion X-ray laser

Lu, P.; Kawachi, Tetsuya; Kishimoto, Maki; Sukegawa, Kota*; Tanaka, Momoko; Hasegawa, Noboru; Suzuki, Masayuki; Tai, R.; Kado, Masataka; Nagashima, Keisuke; et al.

Optics Letters, 27(21), p.1911 - 1913, 2002/11

 Times Cited Count:8 Percentile:40.36(Optics)

We demonstrate a high gain nickel-like xenon ion x-ray laser using a gas puff target. The elongated x-ray laser plasma column was produced by irradiating the gas puff target with line-focused double picosecond laser pulses with a total energy of 18 J in a travelling-wave excitation scheme. Strong lasing at 9.98 nm was observed, and a high gain coefficient of 17.4 1/cm was measured on the transient collisionally excited 4d ミ 4p, J=0-1 transition for nickel-like xenon ion with target lengths up to 0.45 cm long. A weak nickel-like lasing line at a shorter wavelength of 9.64 nm was also observed with a gain coefficient of 5.9 1/cm.

Journal Articles

Development of X-ray laser by transient collisional excitation

Nagashima, Keisuke; Kawachi, Tetsuya; Kado, Masataka; Tanaka, Momoko; Hasegawa, Noboru; Sukegawa, Kota*; Namba, Shinichi; Tang, H.; Daido, Hiroyuki; Kato, Yoshiaki

Purazuma, Kaku Yugo Gakkai-Shi, 78(3), p.248 - 255, 2002/03

no abstracts in English

Journal Articles

Demonstration of a transient high gain soft X-ray laser for neon-like Argon

Lu, P.; Kawachi, Tetsuya; Suzuki, M.*; Sukegawa, Kota*; Namba, Shinichi; Tanaka, Momoko; Hasegawa, Noboru; Nagashima, Keisuke; Daido, Hiroyuki; Arisawa, Takashi; et al.

Japanese Journal of Applied Physics, Part 2, 41(2A), p.L133 - L135, 2002/02

 Times Cited Count:9 Percentile:38.77(Physics, Applied)

no abstracts in English

Journal Articles

Near field imaging of the transient collisional excitation Ni-like Ag X-ray laser

Tanaka, Momoko; Kawachi, Tetsuya; Kado, Masataka; Hasegawa, Noboru; Sukegawa, Kota*; Lu, P.; Nagashima, Keisuke; Kato, Yoshiaki; Takenaka, Hisataka*

Surface Review and Letters, 9(1), p.641 - 644, 2002/02

 Times Cited Count:12 Percentile:54.02(Chemistry, Physical)

no abstracts in English

38 (Records 1-20 displayed on this page)