Faculty Profiles - HISHIKAWA, Akiyoshi

Papers - HISHIKAWA, Akiyoshi

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Compact XFEL and AMO sciences: SACLA and SCSS Reviewed

M. Yabashi, H. Tanaka, T. Tanaka, H. Tomizawa, T. Togashi, M. Nagasono, T. Ishikawa, J. R. Harries, Y. Hikosaka, A. Hishikawa, K. Nagaya, N. Saito, E. Shigemasa, K. Yamanouchi, K. Ueda

JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS Vol. 46 ( 16 ) page： 164001 2013.8

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

The concept, design and performance of Japan's compact free-electron laser (FEL) facilities, the SPring-8 Compact SASE Source test accelerator (SCSS) and SPring-8 Angstrom Compact free electron LAser (SACLA), and their applications in mainly atomic, molecular and optical science are reviewed. At SCSS, intense, ultrafast FEL pulses at extreme ultraviolet (EUV) wavelengths have been utilized for investigating various multi-photon processes in atoms, molecules and clusters by means of ion and electron spectroscopy. The quantum optical effect superfluorescence has been observed with EUV excitation. A pump-probe technique combining FEL pulses with near infrared laser pulses has been realized to study the ultrafast dynamics of atoms, molecules and clusters in the sub-picosecond regime. At SACLA, deep inner-shell multi-photon ionization by intense x-ray FEL pulses has been investigated. The development of seeded FEL sources for producing transversely and temporally coherent light, as well as the expected impact on advanced science are discussed.

DOI： 10.1088/0953-4075/46/16/164001

Web of Science

Scopus

Resonances in three-photon double ionization of Ar in intense extreme ultraviolet free-electron laser fields studied by shot-by-shot photoelectron spectroscopy Reviewed

Y. Hikosaka, M. Fushitani, A. Matsuda, T. Endo, Y. Toida, E. Shigemasa, M. Nagasono, K. Tono, T. Togashi, M. Yabashi, T. Ishikawa and A. Hishikawa

Phys. Rev. A Vol. 88 ( 023421 ) page： 023421 2013.8

Resonances in three-photon double ionization of Ar in intense extreme-ultraviolet free-electron laser fields studied by shot-by-shot photoelectron spectroscopy Reviewed

Y. Hikosaka, M. Fushitani, A. Matsuda, T. Endo, Y. Toida, E. Shigemasa, M. Nagasono, K. Tono, T. Togashi, M. Yabashi, T. Ishikawa, A. Hishikawa

PHYSICAL REVIEW A Vol. 88 ( 2 ) 2013.8

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER PHYSICAL SOC

Shot-by-shot photoelectron spectroscopy has been performed to study the three-photon double ionization of Ar in intense extreme-ultraviolet free-electron laser fields over a photon energy range of 19.6-22.0 eV. It is found that the double ionization to Ar2+ 3p(-2) proceeds sequentially via the formation of singly charged Ar+ 3p(-1) states and is enhanced around photon energies of 20.5 and 21.5 eV. Two types of resonance are identified in the two-photon ionization of the Ar+ 3p(-1) states: (i) resonances to intermediate states at the one-photon energy level and (ii) those to autoionizing states above the Ar2+ ionization threshold.

DOI： 10.1103/PhysRevA.88.023421

Web of Science

Scopus

Time-resolved four-body coulomb explosion imaging of correlated dynamics of hydrogen atoms in acetylene dication Reviewed Open Access

A. Matsuda, M. Fushitani, E. J. Takahashi, A. Hishikawa

EPJ Web of Conferences Vol. 41 2013

Language：English Publishing type：Research paper (international conference proceedings)

The correlated motion of the two deuterium atoms associated with the hydrogen migration and structural deformation to non-planar geometry are identified in acetylene dication by the time-resolved four-body Coulomb explosion imaging. © Owned by the authors, published by EDP Sciences, 2013.

DOI： 10.1051/epjconf/20134102013

Open Access

Web of Science

Scopus

Ultrafast nonlinear double excitations of he in intense EUV FEL fields Reviewed Open Access

M. Fushitani, Y. Hikosaka, A. Matsuda, C. N. Liu, T. Morishita, E. Shigemasa, A. Hishikawa

EPJ Web of Conferences Vol. 41 2013

Language：English Publishing type：Research paper (international conference proceedings)

Three-photon double excitation of He in intense EUV FEL fields is studied by the shot-by-shot photoelectron spectroscopy, revealing the enhancement by resonances to the doubly excited states converging to the He+ N=3 level. © Owned by the authors, published by EDP Sciences, 2013.

DOI： 10.1051/epjconf/20134102009

Open Access

Web of Science

Scopus

Shot-by-Shot Photoelectron Spectroscopy of Rare Gas Atoms in Ultrashort Intense EUV Free-Electron Laser Fields

Mizuho Fushitani, Yasumasa Hikosaka, Akitaka Matsuda, Eiji Shigemasa, Akiyoshi Hishikawa

Springer Series in Chemical Physics page： 151 - 163 2013

Two-electron dynamics in nonlinear double excitation of helium by intense ultrashort extreme-ultraviolet pulses Reviewed

Chien-Nan Liu, Akiyoshi Hishikawa, Toru Morishita

PHYSICAL REVIEW A Vol. 86 ( 5 ) page： 13 2012.11

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER PHYSICAL SOC

We present a theoretical study for multiphoton double excitation of He atoms exposed to an intense ultrashort extreme-ultraviolet (EUV) pulse, where the photon energy coincides with the transition energy from the ground state to a Rydberg state, by solving the time-dependent Schrodinger equation in the hyperspherical coordinates. Photoelectron spectra under the conditions comparable with a recent experiment [Hishikawa et al., Phys. Rev. Lett. 107, 243003 (2011)] are calculated and analyzed. We identify the mechanism of the enhanced three-photon absorption probability which is more than one order of magnitude larger than that for the two-photon process in accordance with the experiment. The enhancement is attributed to a propensity rule for double excitation in a two-step mechanism, in which a one-photon absorption by one electron to a Rydberg state is followed by a two-photon absorption by the other electron to an excited orbital, while the first electron remains at nearly the same principle quantum number. Based on the time-dependent perturbation theory, the three-photon absorption probability exhibits peculiar cubic dependence on the pulse duration due to the propensity rule, in contrast to the linear dependence of the two-photon absorption probability. Thus a crossover between the two-and three-photon absorption probabilities takes place for sufficiently intense and long pulses. We also study the time evolution of a doubly excited two-electron wave packet created by an intense ultrashort EUV pulse efficiently using the same enhancement scheme, opening up the possibility of visualizing the correlated motion of two electrons in the time domain.

DOI： 10.1103/PhysRevA.86.053426

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Scopus

レーザークーロン爆発イメージングによる実時間反応追跡 Invited Reviewed

菱川明栄

レーザー研究 Vol. 40 page： 745-751 2012.10

EUV and soft X-ray photoelectron spectroscopy of isolated atoms and molecules using single-order laser high-harmonics at 42 eV and 91 eV Reviewed

M. Fushitani, A. Matsuda and A. Hishikawa

J. Electron. Spectrosc. Relat. Phenom. Vol. 184 page： 561-568 2012.2

極紫外自由電子レーザー場における原子のシングルショット光電子分光 Invited Reviewed

彦坂泰正，伏谷瑞穂，菱川明栄

しょうとつ Vol. 9 ( 1 ) page： 5-10 2012.1

EUV and soft X-ray photoelectron spectroscopy of isolated atoms and molecules using single-order laser high-harmonics at 42 eV and 91 eV Reviewed

Mizuho Fushitani, Akitaka Matsuda, Akiyoshi Hishikawa

JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA Vol. 184 ( 11-12 ) page： 561 - 568 2012.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Photoelectron spectroscopy of isolated atoms and molecules using single-order high-harmonics of Ti:Sapphire laser pulses (800 nm, 12 fs/30 fs) is demonstrated. Dielectric multilayer mirrors, SiC/Mg and Mo/Si, are used to isolate the 27th (42 eV) and 59th (91 eV) order harmonics, respectively. The obtained harmonics are characterized by valence and inner-shell photoelectron spectroscopy of Xe. The applications to two-color two-photon ionization of He and pump-probe spectroscopy of ultrafast photodissociation of Br-2, Br-2(C-1 Pi(u)) --> Br(P-2(3/2))+ Br(P-2(3/2)), are presented. (C) 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.elspec.2011.10.002

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Scopus

Theoretical study of multi-photon double electron excitation of He by intense ultrashort EUV pulses Reviewed

Chien-Nan Liu, Toru Morishita, Shinichi Watanabe, Akiyoshi Hishikawa

XXVII INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC AND ATOMIC COLLISIONS (ICPEAC 2011), PTS 1-15 Vol. 388 ( PART 3 ) 2012

Language：Japanese Publishing type：Research paper (international conference proceedings) Publisher：IOP PUBLISHING LTD

We use the time-dependent hypersperhical close-coupling method to study the double excitation of helium atoms by intense ultrashort XUV pulses. In addition to showing the photoelectron yield spectra, we demonstrate that free electron lasers can be used to efficiently create doubly excited electron wave packets, opening up the possibility of visualizing the correlated motion of electrons in atoms.

DOI： 10.1088/1742-6596/388/3/032007

Web of Science

Scopus

Visualizing correlated dynamics of hydrogen atoms in acetylene dication by time-resolved four-body coulomb explosion imaging Reviewed

Akitaka Matsuda, Mizuho Fushitani, Eiji J. Takahashi, Akiyoshi Hishikawa

Springer Proceedings in Physics Vol. 125 page： 317 - 322 2012

Language：English Publishing type：Research paper (international conference proceedings) Publisher：Springer Science and Business Media, LLC

Ultrafast hydrogenmigration in deuterated acetylene dication (C 2D2+2 ) is studied by time-resolved four-body Coulomb explosion imaging, C2D4+ 2 → D++ C ++ C ++ D +, using a pair of few-cycle intense laser pulses (9 fs, 1.3 × 1014 W/cm 2). Momentum correlation of the D+ ions produced by the full fragmentation process shows that (1) motions of the two deuterium atoms are strongly correlated during the isomerization and (2) the molecular structure deforms to nonplanar geometries. © Springer-Verlag Berlin Heidelberg 2012.

DOI： 10.1007/978-3-642-28948-4_53

Scopus

Enhanced Nonlinear Double Excitation of He in Intense Extreme Ultraviolet Laser Fields Reviewed

A. Hishikawa, M. Fushitani, Y. Hikosaka, A. Matsuda, C. -N. Liu, T. Morishita, E. Shigemasa, M. Nagasono, K. Tono, T. Togashi, H. Ohashi, H. Kimura, Y. Senba, M. Yabashi, T. Ishikawa

PHYSICAL REVIEW LETTERS Vol. 107 ( 24 ) page： 243003 2011.12

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER PHYSICAL SOC

Nonlinear, three-photon double excitation of He in intense extreme ultraviolet free-electron laser fields (similar to 24.1 eV, similar to 5 TW/cm(2)) is presented. Resonances to the doubly excited states converging to the He(+) N = 3 level are revealed by the shot-by-shot photoelectron spectroscopy and identified by theoretical calculations based on the time-dependent Schrodinger equation for the two-electron atom under a laser field. It is shown that the three-photon double excitation is enhanced by intermediate Rydberg states below the first ionization threshold, giving a greater contribution to the photoionization yields than the two-photon process by more than 1 order of magnitude.

DOI： 10.1103/PhysRevLett.107.243003

Web of Science

Scopus

PubMed

クーロン爆発イメージングによる超高速反応追跡 Invited

菱川明栄

光アライアンス Vol. 22 ( 11 ) page： 19-22 2011.11

光のゆらぎで探る：自由電子レーザー場中の原子 Invited

伏谷瑞穂, 彦坂泰正, 菱川明栄

光アライアンス Vol. 22 ( 10 ) page： 25-28 2011.10

A magnetic-bottle multi-electron-ion coincidence spectrometer Reviewed

Akitaka Matsuda, Mizuho Fushitani, Chien-Ming Tseng, Yasumasa Hikosaka, John H. D. Eland, Akiyoshi Hishikawa

REVIEW OF SCIENTIFIC INSTRUMENTS Vol. 82 ( 10 ) page： 103105 2011.10

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER INST PHYSICS

A novel multi-electron-ion coincidence spectrometer developed on the basis of a 1.5 m-long magnetic-bottle electron spectrometer is presented. Electrons are guided by an inhomogeneous magnetic field to a detector at the end of the flight tube, while a set of optics is used to extract counterpart ions to the same detector, by a pulsed inhomogeneous electric field. This setup allows ion detection with high mass resolution, without impairing the high collection efficiency for electrons. The performance of the coincidence spectrometer was tested with double ionization of carbon disulfide, CS2 -> CS22+ + e(-) + e(-), in ultrashort intense laser fields (2.8 x 10(13) W/cm(2), 280 fs, 1030 nm) to clarify the electron correlation below the rescattering threshold. (C) 2011 American Institute of Physics. [doi:10.1063/1.3648133]

DOI： 10.1063/1.3648133

Web of Science

Scopus

PubMed

Time-resolved EUV photoelectron spectroscopy of dissociating I-2 by laser harmonics at 80 nm Reviewed Open Access

Mizuho Fushitani, Akitaka Matsuda, Akiyoshi Hishikawa

OPTICS EXPRESS Vol. 19 ( 10 ) page： 9600 - 9606 2011.5

Language：English Publishing type：Research paper (scientific journal) Publisher：OPTICAL SOC AMER

Generation of single-order laser harmonics in extreme ultraviolet (EUV) and the application to the time-resolved photoelectron spectroscopy of I-2 are demonstrated. The EUV pulses at 80 nm were generated from Kr as the 5th order harmonics of intense 400 nm laser pulses and then separated from other harmonic orders by a thin indium foil. The pump-probe photoelectron spectroscopy of I-2 in the B (3)Pi(0(u)(+)) and B" (1)Pi(1(u)) states excited by visible laser pulses at 490 nm showed a rapid increase in the yield of atomic iodine (similar to 400 fs), reflecting the dissociation dynamics evolving simultaneously in the two excited states. (C) 2011 Optical Society of America

DOI： 10.1364/OE.19.009600

Time-resolved EUV photoelectron spectroscopy of dissociating I(2) by laser harmonics at 80 nm Reviewed

Fushitani, M. and Matsuda, A. and Hishikawa, A.

Optics Express Vol. 19 ( 10 ) page： 9600-9606 2011

Language：English Publishing type：Research paper (scientific journal)

Generation of single-order laser harmonics in extreme ultraviolet (EUV) and the application to the time-resolved photoelectron spectroscopy of I(2) are demonstrated. The EUV pulses at 80 nm were generated from Kr as the 5th order harmonics of intense 400 nm laser pulses and then separated from other harmonic orders by a thin indium foil. The pump-probe photoelectron spectroscopy of I(2) in the B (3)Pi(0(u)(+)) and B" (1)Pi(1(u)) states excited by visible laser pulses at 490 nm showed a rapid increase in the yield of atomic iodine (similar to 400 fs), reflecting the dissociation dynamics evolving simultaneously in the two excited states. (C) 2011 Optical Society of America

Visualizing hydrogen atoms migrating in acetylene dication by time-resolved three-body and four-body Coulomb explosion imaging Reviewed

Matsuda, A. and Fushitani, M. and Takahashi, E. J. and Hishikawa, A.

Physical Chemistry Chemical Physics Vol. 13 ( 19 ) page： 8697-8704 2011

Language：English Publishing type：Research paper (scientific journal)

The visualization of ultrafast isomerization of deuterated acetylene dication (C(2)D(2)(2+)) is demonstrated by time-resolved Coulomb explosion imaging with sub-10 fs intense laser pulses ( 9 fs, 0.13 PW cm(-2), 800 nm). The Coulomb explosion imaging monitoring the three-body explosion process, C(2)D(2)(3+) -> D(+) + C(+) + CD(+), as a function of the delay between the pump and probe pulses revealed that the migration of a deuterium atom proceeds in a recurrent manner; One of the deuterium atoms first shifts from one carbon site to the other in a short timescale (similar to 90 fs), and then migrates back to the original carbon site by 280 fs, in competition with the molecular dissociation. Correlated motion of the two deuterium atoms associated with the hydrogen migration and structural deformation to non-planar geometry are identified by the time-resolved four-body Coulomb explosion imaging, C(2)D(2)(4+) - D(+) + C(+) + C(+) + D(+).

DOI： Doi 10.1039/C0cp02333g

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Papers - HISHIKAWA, Akiyoshi