研究者詳細 - 伏谷　瑞穂

論文 - 伏谷　瑞穂

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Photoelectron sidebands induced by a chirped laser field for shot-by-shot temporal characterization of FEL pulses 査読有り

Liu Chien-Nan, Morishita Toru, Fushitani Mizuho, Hishikawa Akiyoshi

JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS 49 巻 ( 3 ) 2016年2月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Physics B: Atomic, Molecular and Optical Physics

We theoretically investigate the laser-assisted photoionization of He by an extreme ultra violet (XUV) pulse in the presence of a linearly chirped intense laser pulse by solving the time-dependent Schrödinger equation within the single-active-electron approximation. Analysis based on the time-dependent perturbation theory is also carried out to provide more physical insights. A new scheme is shown to be capable of extracting the arrival time of an XUV free-electron laser (FEL) pulse relative to an external laser pulse as well as the XUV pulse duration from the photoelectron sidebands resulting from XUV ionization in the presence of a chirped laser pulse. This scheme is independent of the energy fluctuation and the timing jittering of the FEL pulse. Therefore it can be implemented in a non-invasive way to characterize FEL pulses on a shot-by-shot basis in time-resolved spectroscopy.

DOI： 10.1088/0953-4075/49/3/034005

Coincidence momentum imaging of asymmetric Coulomb explosion of CO2 in phase-locked two-color intense laser fields 査読有り

Endo Tomoyuki, Fujise Hikaru, Matsuda Akitaka, Fushitani Mizuho, Kono Hirohiko, Hishikawa Akiyoshi

JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 207 巻頁： 50 - 54 2016年2月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Electron Spectroscopy and Related Phenomena

Coulomb explosion of CO2, CO2 → CO22+ + 2e- → CO+ + O+ + 2e-, in phase-locked two-color ultrashort intense laser fields (800 nm and 400 nm, ∼1014 W/cm2) has been investigated by coincidence momentum imaging. The momentum images of the O+ and CO+ fragments show asymmetric distributions along the laser polarization direction depending on the relative phase of the two-color laser fields. The fragment asymmetry becomes most prominent (∼4%) at the relative phases providing the largest asymmetry of the electric field amplitude, with the O+ fragments preferentially ejected to the stronger field side. The mechanism of the asymmetric bond breaking of the two equivalent C-O bonds is discussed in terms of the nuclear dynamics in CO22+.

DOI： 10.1016/j.elspec.2015.12.010

22pAE-11 極紫外レーザー高次高調波によるN_2リュードベリ波束ダイナミクスの超高速光電子分光

伏谷瑞穂, 樋田裕斗, Legare Francois, 菱川明栄

日本物理学会講演概要集 71 巻頁： 819 - 819 2016年

Correlation between Photoeletron and Photoion in Ultrafast Multichannel Photoionization of Ar 査読有り

Itakura R., Fushitani M., Hishikawa A., Sako T.

INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2015 (ICCMSE 2015) 1702 巻 2015年

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：AIP Conference Proceedings

We theoretically investigate coherent dynamics of ions created through ultrafast multichannel photoionization from a viewpoint of photoelectron-photoion correlation. The model calculation on single-photon ionization of Ar reveals that the coherent hole dynamics in Ar+ associated with a superposition of the spin-orbit states 2PJ (J = 3/2 and 1/2) can be identified by monitoring only the photoion created by a Fourier-transform limited extreme ultraviolet (EUV) pulse with the fs pulse duration, while the coherence is lost by a chirped EUV pulse. It is demonstrated that by coincidence detection of the photoelectron and photoion the coherent hole dynamics can be extracted even in the case of ionization by a chirped EUV pulse with the sufficiently wide bandwidth.

DOI： 10.1063/1.4938829

Ion-Coincidence Momentum Imaging of Three-Body Coulomb Explosion of Formaldehyde in Ultrashort Intense Laser Fields 査読有り

Fushitani M., Tseng C-M., Matsuda A., Hishikawa A.

INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2015 (ICCMSE 2015) 1702 巻 2015年

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：AIP Conference Proceedings

Three-body Coulomb explosion of formaldehyde (H2CO) in intense 7- and 35-fs laser fields (1.3 × 1015 W/cm2) has been investigated by using ion-coincidence momentum imaging technique. Two types of explosion pathways from the triply charged state, H2CO3+ → (i) H+ + H+ + CO+ and (ii) H+ + CH+ + O+, have been identified. It is shown from the momentum correlation of the fragment ions of pathway (i), that the geometrical structure of the molecule is essentially frozen along the H-C-H bending coordinate for the 7-fs case. On the other hand, for a longer pulse duration (35 fs), structural deformation along the C-H stretching and H-C-H bending coordinates is identified, which is ascribed to the nuclear dynamics in the dication states populated within the laser pulse duration.

DOI： 10.1063/1.4938821

Fragment anisotropy on dissociative ionization of NO in two-color intense laser fields 査読有り

Endo Tomoyuki, Ishihara Ayaka, Matsuda Akitaka, Fushitani Mizuho, Hishikawa Akiyoshi

XXIX INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC, AND ATOMIC COLLISIONS (ICPEAC2015), PTS 1-12 635 巻 ( 11 ) 2015年

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Journal of Physics: Conference Series

Dissociative ionization of NO, NO → NO+ + e- → N+ + O + e-, in ω-2ω two-color phase-controlled intense laser fields was investigated by three-dimensional ion momentum imaging. The momentum image of the N+ ion exhibited anisotropic distributions peaked at 35° against the laser polarization, which show clear left-right asymmetry depending on the ω-2ω relative phase. The present study demonstrates that the molecular orbital can be retrieved by distinguishing the difference between the N and O side from the fragment anisotropy by intense laser pulses.

DOI： 10.1088/1742-6596/635/11/112027

その他リンク： http://orcid.org/0000-0003-1444-8917

Determination of Absolute Cross-Sections of Nonresonant EUV-UV Two-Color Two-Photon Ionization of He 査読有り

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

ULTRAFAST PHENOMENA XIX 162 巻頁： 109 - 112 2015年

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Springer Proceedings in Physics

Single-shot photoelectron spectroscopy was performed for nonresonant EUV-UV two-color two-photon ionization of He. From data analysis on the shotby- shot basis, the absolute cross-section was determined to be σ(2) (59.7 nm, 268 nm) = 4.1(6) × 10-52 cm4 s.

DOI： 10.1007/978-3-319-13242-6_26

その他リンク： http://orcid.org/0000-0003-1444-8917

Ultrafast two-photon Rabi oscillations in excited He driven by femtosecond intense laser fields 査読有り

Hishikawa A., Fushitani M., Liu C. N., Matsuda A., Endo T., Toida Y., Hikosaka Y., Morishita T.

XXIX INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC, AND ATOMIC COLLISIONS (ICPEAC2015), PTS 1-12 635 巻 ( 9 ) 2015年

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Journal of Physics: Conference Series

We demonstrate ultrafast multiphoton coherent excitation in near-infrared intense laser fields (≤10 TW/cm2) using excited helium in the 1s2p (1P) state as the target. Strong two-photon coupling between the 2p state and the 5f and 6f Rydberg states drives ultrafast Rabi oscillations in tens of femtosecond. Theoretical calculations solving the time-dependent Schrodinger equation were carried out to elucidate the strong field effects.

DOI： 10.1088/1742-6596/635/9/092082

その他リンク： http://orcid.org/0000-0003-1444-8917

Five-photon sequential double ionization of He in intense extreme-ultraviolet free-electron laser fields 査読有り

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 90 巻頁： 053403 2014年11月

Five-photon sequential double ionization of He in intense extreme-ultraviolet free-electron laser fields 査読有り

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

PHYSICAL REVIEW A 90 巻 ( 5 ) 2014年11月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review A - Atomic, Molecular, and Optical Physics

A multiphoton ionization process of He in intense extreme ultraviolet free-electron laser fields is investigated in a photon energy range of hv=20.1-20.8eV using shot-by-shot photoelectron spectroscopy. A photoelectron peak resulting from sequential double ionization of He due to five-photon absorption is observed around hv=20.4. Shot-by-shot analysis of photoelectron spectra shows that two-photon resonance to the He+(2s2S) state from the He+ ground state is responsible for the substantial enhancement of five-photon double ionization. Effective cross sections for two-photon absorption between the 1s and 2s states of He+ and for one-photon absorption from the He+ 2s state are obtained.

DOI： 10.1103/PhysRevA.90.053403

Photoelectron-photoion correlation in ultrafast multichannel photoionization of Ar 査読有り

Itakura R., Fushitani M., Hishikawa A., Sako T.

JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS 47 巻 ( 19 ) 頁： 195602 2014年10月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Physics B: Atomic, Molecular and Optical Physics

Ultrafast multichannel single-photon ionization of Ar is investigated theoretically by a model calculation incorporating correlation between the photoelectron and photoion. It is shown that the coherent hole dynamics in Ar+associated with a superposition of the spin-orbit states can be observed by using a Fourier-transform limited laser pulse for ionization, while the coherence is degraded or lost by chirped a laser pulse. We demonstrate that the coherent hole dynamics can be retrieved even in the case of ionization by a chirped laser pulse, by labeling the photoion dynamics with the counterpart photoelectron energy.

DOI： 10.1088/0953-4075/47/19/195602

Dissociative ionization of NO in few-cycle intense laser fields : Effects of pi-sigma electronic transition 査読有り

Endo Tomoyuki, Fushitani Mizuho, Matsuda Akitaka, Hishikawa Akiyoshi

XXVIII INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC AND ATOMIC COLLISIONS (ICPEAC) 488 巻 ( SECTION 3 ) 2014年

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Journal of Physics: Conference Series

Dissociative ionization (DI) of NO in few-cycle intense laser fields was investigated by using the 3D momentum imaging method. It was found that the symmetry change in the outermost occupied molecular orbital upon the π-σ electronic transition is clearly reflected in the spatial anisotropy of the fragmention, N+.

DOI： 10.1088/1742-6596/488/3/032025

その他リンク： http://orcid.org/0000-0003-1444-8917

Two-photon rabi oscillations of excited he atoms in ultrafast strong laser field ionization 査読有り

Fushitani M, Liu C.-N, Matsuda A, Endo T, Toida Y, Hikosaka Y, Nagasono M, Togashi T, Yabashi M, Ishikawa T, Morishita T, Hishikawa A

Optics InfoBase Conference Papers 2014年

Nonresonant EUV-UV two-color two-photon ionization of He studied by single-shot photoelectron spectroscopy 査読有り

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

PHYSICAL REVIEW A 88 巻 ( 6 ) 頁： 063422 2013年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review A - Atomic, Molecular, and Optical Physics

Single-shot photoelectron spectroscopy of nonresonant two-color two-photon ionization of He has been carried out using an intense free-electron laser (FEL) at 59.7 nm and a femtosecond UV laser at 268 nm. By shot-by-shot analysis of photoelectron spectra, the cross section for nonresonant two-color ionization of He is determined to be σ(2)=4.1(6)×10-52 cm4 s. The cross-correlation trace derived from the nonresonant signals shows that the temporal resolution of the system is 0.36(3) ps, which is mainly governed by the timing jitter between the FEL and UV laser pulses. © 2013 American Physical Society.

DOI： 10.1103/PhysRevA.88.063422

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

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

PHYSICAL REVIEW A 88 巻 ( 2 ) 頁： 023421 2013年8月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review A - Atomic, Molecular, and Optical Physics

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 Ar+ ionization threshold. © 2013 American Physical Society.

DOI： 10.1103/PhysRevA.88.023421

Time-resolved Four-body Coulomb Explosion Imaging of Correlated Dynamics of Hydrogen Atoms in Acetylene Dication 査読有り

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

XVIIITH INTERNATIONAL CONFERENCE ON ULTRAFAST PHENOMENA 41 巻 2013年

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：EPJ Web of Conferences

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

Ultrafast Nonlinear Double Excitations of He in Intense EUV FEL Fields 査読有り

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

XVIIITH INTERNATIONAL CONFERENCE ON ULTRAFAST PHENOMENA 41 巻 2013年

記述言語：日本語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：EPJ Web of Conferences

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

Phase Sensitive Control of Vibronic Guest-Host Interaction: Br-2 in Ar Matrix (vol 113, pg 7439, 2009) 査読有り

Heide Ibrahim, Monika Hejjas, Mizuho Fushitani, Nikolaus Schwentner

JOURNAL OF PHYSICAL CHEMISTRY A 116 巻 ( 10 ) 頁： 2598 - 2598 2012年3月

Erratum: Phase sensitive control of vibronic guest-host interaction: Br <inf>2</inf> in Ar matrix (Journal of Physical Chemistry A (2009) 113: 26 (7439-7450) DOI: 10.1021/jp900287m) 査読有り

Ibrahim, H., Héjjas, M., Fushitani, M., Schwentner, N.

Journal of Physical Chemistry A 116 巻 ( 10 ) 頁： 2598 - 2598 2012年

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

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

Springer Proceedings in Physics 125 巻頁： 317 - 322 2012年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Springer Proceedings in Physics

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

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