研究者詳細 - 菱川　明栄

論文 - 菱川　明栄

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Selective-bond breaking of CF4 in phase-locked ω-2ω intense laser fields

Hiroka Hasegawa, Tiffany Walmsley, Akitaka Matsuda, Toru Morishita, Lars Bojer Madsen, Frank Jensen, Oleg I. Tolstikhin, Akiyoshi Hishikawa

The International Conference on Ultrafast Phenomena (UP) 2022 2022年

Association Reaction of Gaseous C<sub>2</sub>H<sub>4</sub> in Femtosecond Laser Filaments Studied by Time-of-Flight Mass Spectrometry 査読有り Open Access

Matsuda, A; Tani, K; Takeuchi, Y; Hayakawa, Y; Hishikawa, A

ACS OMEGA 6 巻 ( 44 ) 頁： 29862 - 29868 2021年11月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ACS Omega

Association reactions by femtosecond laser filamentation in gaseous C2H4 were studied by time-of-flight mass spectrometry of neutral reaction products. Direct sampling from the reaction cell to a mass spectrometer via a differential pumping stage allowed the identification of various hydrocarbon molecules CnHm with n = 3-7 and m = 4-7, which includes species not observed in the previous studies. It was found that products containing three and four carbon atoms dominate the mass spectrum with smaller yields for higher-mass species, suggesting that carbon chain growth proceeds through the reaction with C2H4 in the reaction cell. The product distribution showed a clear dependence on the laser pulse energy for filamentation.

DOI： 10.1021/acsomega.1c04354

Time-resolved shot-by-shot photoelectron spectroscopy of autoionizing Xe<SUP>+</SUP> states by EUV-free-electron-laser and near-IR laser pulses 査読有り

Fushitani, M; Kawabe, Y; Fujise, H; Yamada, M; Hasegawa, H; Owada, S; Togashi, T; Nakajima, K; Yabashi, M; Matsuda, A; Hikosaka, Y; Hishikawa, A

PHYSICAL REVIEW A 104 巻 ( 2 ) 2021年8月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review A

Ultrafast dynamics of highly excited Rydberg states of is investigated by time-resolved shot-by-shot photoelectron spectroscopy with EUV-free-electron-laser pump (40.8 eV) and near-infrared probe (1.56 eV) pulses. Sorting the single-shot spectra in the order of relative delay between the two pulses allows for investigating ultrafast decays of intermediate states participating in the double ionization of Xe. Observed photoelectron spectra show a biexponential decay within ∼100 fs and ∼300 ps in addition to constant signals lasting longer than 1 ns. These ultrafast decays reflect the lifetimes of autoionizing Rydberg states converging to electronically excited states of . The results demonstrate that time-resolved shot-by-shot EUV-free-electron-laser photoelectron spectroscopywith a synchronized optical laser provides a powerful tool for investigating ultrafast electron emission processes.

DOI： 10.1103/PhysRevA.104.023102

その他リンク： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevA.104.023102/fulltext

Time-resolved photoelectron imaging of complex resonances in molecular nitrogen 査読有り国際共著 Open Access

Fushitani, M; Pratt, ST; You, D; Saito, S; Luo, Y; Ueda, K; Fujise, H; Hishikawa, A; Ibrahim, H; Légaré, F; Johnsson, P; Peschel, J; Simpson, ER; Olofsson, A; Mauritsson, J; Carpeggiani, PA; Maroju, PK; Moioli, M; Ertel, D; Shah, R; Sansone, G; Csizmadia, T; Dumergue, M; Harshitha, NG; Kühn, S; Callegari, C; Plekan, O; Di Fraia, M; Danailov, MB; Demidovich, A; Giannessi, L; Raimondi, L; Zangrando, M; De Ninno, G; Prince, KC

JOURNAL OF CHEMICAL PHYSICS 154 巻 ( 14 ) 頁： 144305 - 144305 2021年4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 Chemical Physics

We have used the FERMI free-electron laser to perform time-resolved photoelectron imaging experiments on a complex group of resonances near 15.38 eV in the absorption spectrum of molecular nitrogen, N2, under jet-cooled conditions. The new data complement and extend the earlier work of Fushitani et al. [Opt. Express 27, 19702-19711 (2019)], who recorded time-resolved photoelectron spectra for this same group of resonances. Time-dependent oscillations are observed in both the photoelectron yields and the photoelectron angular distributions, providing insight into the interactions among the resonant intermediate states. In addition, for most states, we observe an exponential decay of the photoelectron yield that depends on the ionic final state. This observation can be rationalized by the different lifetimes for the intermediate states contributing to a particular ionization channel. Although there are nine resonances within the group, we show that by detecting individual photoelectron final states and their angular dependence, we can identify and differentiate quantum pathways within this complex system.

DOI： 10.1063/5.0046577

その他リンク： https://aip.scitation.org/doi/pdf/10.1063/5.0046577

On the measurement of statistical dynamics using the method of Coulomb explosion imaging

Endo T., Neville S.P., Wanie V., Beaulieu S., Qu C., Lassonde P., Schmidt B.E., Fujise H., Fushitani M., Hishikawa A., Houston P.L., Bowman J.M., Schuurman M.S., Légaré F., Ibrahim H.

AIP Conference Proceedings 2343 巻 2021年3月

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

Using time-resolved Coulomb explosion imaging (CEI) in an ultraviolet (UV) pump near infrared (NIR) probe experiment, we directly image the different dissociation dynamics in the formaldehyde molecule. Different pathways are distinguished from each other, despite their statistical nature. To extract such dynamics, hidden in a statistical background, calls for an elimination of noise. In our approach, we take advantage of CEI being a quasi-background-free technique.

DOI： 10.1063/5.0047930

Capturing roaming molecular fragments in real time 査読有り国際共著国際誌

Endo, T; Neville, SP; Wanie, V; Beaulieu, S; Qu, C; Deschamps, J; Lassonde, P; Schmidt, BE; Fujise, H; Fushitani, M; Hishikawa, A; Houston, PL; Bowman, JM; Schuurman, MS; Légaré, F; Ibrahim, H

SCIENCE 370 巻 ( 6520 ) 頁： 1072 - + 2020年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Science

Since the discovery of roaming as an alternative molecular dissociation pathway in formaldehyde (H2CO), it has been indirectly observed in numerous molecules. The phenomenon describes a frustrated dissociation with fragments roaming at relatively large interatomic distances rather than following conventional transition-state dissociation; incipient radicals from the parent molecule self-react to form molecular products. Roaming has been identified spectroscopically through static product channel- resolved measurements, but not in real-time observations of the roaming fragment itself. Using timeresolved Coulomb explosion imaging (CEI), we directly imaged individual "roamers"on ultrafast time scales in the prototypical formaldehyde dissociation reaction. Using high-level first-principles simulations of all critical experimental steps, distinctive roaming signatures were identified. These were rendered observable by extracting rare stochastic events out of an overwhelming background using the highly sensitive CEI method.

DOI： 10.1126/science.abc2960

Capturing roaming fragments in real time: A molecular road movie

Endo T., Neville S.P., Wanie V., Beaulieu S., Qu C., Deschamps J., Lassonde P., Schmidt B.E., Fujise H., Fushitani M., Hishikawa A., Houston P.L., Bowman J.M., Schuurman M.S., Légaré F., Ibrahim H.

Optics InfoBase Conference Papers 2020年11月

記述言語：日本語出版者・発行元：Optics InfoBase Conference Papers

"Roamers" are directly observed in the prototypical roaming reaction in the formaldehyde molecule. Despite their statistical nature, roaming is well discriminated from the radical- and molecular dissociation channels, using Coulomb explosion imaging and theoretical modeling.

DOI： 10.1364/UP.2020.Th4A.1

Ultrafast Reaction Imaging and Control by Ultrashort Intense Laser Pulses 招待有り査読有り Open Access

Hishikawa, A; Matsuda, A; Fushitani, M

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 93 巻 ( 11 ) 頁： 1293 - 1304 2020年11月

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Bulletin of the Chemical Society of Japan

Molecules irradiated with intense laser pulses (field intensity ∼1015W/cm2) exhibit a variety of characteristic processes, such as tunneling ionization, electron rescattering, high-order harmonics generation and Coulomb explosion, that cannot be seen in a weak light field. These features have attracted attention in the last decades as they provide unique approaches to visualize and manipulate ultrafast dynamics of atoms and molecules. Here we discuss molecular processes in intense laser fields, with focuses on the applications to ultrafast imaging and control of reaction dynamics.

DOI： 10.1246/bcsj.20200158

Characterization of soft X-ray FEL pulse duration with two-color photoelectron spectroscopy 査読有り

Owada, S; Fushitani, M; Matsuda, A; Fujise, H; Sasaki, Y; Hikosaka, Y; Hishikawa, A; Yabashi, M

JOURNAL OF SYNCHROTRON RADIATION 27 巻 ( 5 ) 頁： 1362 - 1365 2020年9月

Multielectron-Ion Coincidence Spectroscopy of Xe in Extreme Ultraviolet Laser Fields: Nonlinear Multiple Ionization via Double Core-Hole States 査読有り国際誌

Fushitani, M; Sasaki, Y; Matsuda, A; Fujise, H; Kawabe, Y; Hashigaya, K; Owada, S; Togashi, T; Nakajima, K; Yabashi, M; Hikosaka, Y; Hishikawa, A

PHYSICAL REVIEW LETTERS 124 巻 ( 19 ) 2020年5月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review Letters

Ultrafast multiphoton ionization of Xe in strong extreme ultraviolet free-electron laser (FEL) fields (91 eV, 30 fs, 1.6×1012 W/cm2) has been investigated by multielectron-ion coincidence spectroscopy. The electron spectra recorded in coincidence with Xe4+ show characteristic features associated with two-photon absorption to the 4d-2 double core-hole (DCH) states and subsequent Auger decay. It is found that the pathway via the DCH states, which has eluded clear identification in previous studies, makes a large contribution to the multiple ionization, despite the long FEL pulse duration compared with the lifetime of the 4d core-hole states.

DOI： 10.1103/PhysRevLett.124.193201

その他リンク： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.124.193201/fulltext

Angle dependence of dissociative tunneling ionization of NO in asymmetric two-color intense laser fields 査読有り

Endo, T; Fujise, H; Hasegawa, H; Matsuda, A; Fushitani, M; Tolstikhin, OI; Morishita, T; Hishikawa, A

PHYSICAL REVIEW A 100 巻 ( 5 ) 頁： 053422 2019年11月

担当区分：最終著者,　責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review A

Dissociative tunneling ionization of nitric oxide (NO) in linearly polarized phase-locked two-color femtosecond intense laser fields (45 fs, λ=800 and 400 nm, total field intensity I=1×1014W/cm2) has been studied by three-dimensional ion momentum imaging. The N+ fragment produced by the dissociative ionization, NO→NO++e-→N++O+e-, exhibits a butterflylike momentum distribution peaked at finite angles with respect to the laser polarization direction. In addition, a clear dependence on the relative phase between the two laser fields is observed, showing that the tunneling ionization occurs efficiently when the electric field points from N to O. For the highest kinetic energy component, the observed orientation dependence is well explained with theoretical calculations by the weak-field asymptotic theory for the 2πhighest occupied molecular orbital (HOMO). On the other hand, the peak angle shifts toward the laser polarization direction as the kinetic energy decreases, indicating that pathways other than direct ionization from the HOMO contribute to the dissociative ionization.

DOI： 10.1103/PhysRevA.100.053422

Probing Rydberg-Rydberg interactions in N<sub>2</sub> by ultrafast EUV-NIR photoelectron spectroscopy 査読有り国際共著 Open Access

Fushitani, M; Toida, Y; Légaré, F; Hishikawa, A

OPTICS EXPRESS 27 巻 ( 14 ) 頁： 19702 - 19711 2019年7月

担当区分：最終著者,　責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Optics Letters

The ultrafast dynamics of molecular nitrogen (N2) just below the ionization threshold has been investigated by time-resolved photoelectron spectroscopy using a single harmonic centered at hν = 15.38 eV. The evolution of the Rydberg wavepacket launched by the ultrashort EUV pulse is probed by a time-delayed femtosecond NIR laser pulse. The observed photoelectron spectra show two series of vibrational peaks to the ground X2Σg+ state and the first excited A2Πu state of N+2 . Among these, two photoelectron peaks with the vibrational quantum numbers vX+ = 4 and vA+ = 1 exhibit clear anti-phase oscillations with a period of 300 fs, showing that two Rydberg states converging to the X2Σg+ and A2Πu ionic states interact with each other, thus causing periodic switching in the population of the ion core states.

DOI： 10.1364/OE.27.019702

Coincidence momentum imaging of four- and three-body Coulomb explosion of formaldehyde in ultrashort intense laser fields 査読有り国際共著

Tseng, CM; Fushitani, M; Matsuda, A; Hishikawa, A

JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 228 巻頁： 25 - 30 2018年10月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Electron Spectroscopy and Related Phenomena

Ion-coincidence momentum imaging of Coulomb explosion of formaldehyde (H2CO) in femtosecond intense laser fields (800 nm, 1.3 × 1015 W/cm2) is performed with two different laser pulse durations (7 fs and 35 fs). In the 7-fs laser fields, the full fragmentation pathway from H2CO4+ → H+ + H+ + C+ + O+ is identified. The angles between the fragment momenta are well reproduced by a simple Coulomb explosion model from the geometry of neutral formaldehyde, showing that the molecular structure is virtually frozen along the bending coordinates during the multiple ionization. Three-body Coulomb explosion pathways from triply charged states, H2CO3+ → H+ + H+ + CO+ and H+ + CH+ + O+, are observed in both the 7-fs and 35-fs laser fields. Significant changes in the momentum angle distribution and asymmetric energy partitioning between two H+ ions are observed in the 35-fs case, which are attributed to structural deformation prior to the Coulomb explosion in the longer pulse.

DOI： 10.1016/j.elspec.2018.07.001

Femtosecond laser filamentation in gaseous ethylene: Formation of hydrogenated amorphous carbon 査読有り

A. Matsuda, T. Hayashi, R. Kitaura, A. Hishikawa

Chem. Lett. 46 巻頁： 1426-1429 2017年7月

Selective bond breaking of CO<sub>2</sub> in phase-locked two-color intense laser fields: laser field intensity dependence 査読有り Open Access

Endo, T; Fujise, H; Kawachi, Y; Ishihara, A; Matsuda, A; Fushitani, M; Kono, H; Hishikawa, A

PHYSICAL CHEMISTRY CHEMICAL PHYSICS 19 巻 ( 5 ) 頁： 3550 - 3556 2017年2月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Chemistry Chemical Physics

Selective bond breaking of CO2 in phase-locked ω-2ω two-color intense laser fields (λ = 800 nm and 400 nm, total field intensity I ∼ 1014 W cm-2) has been investigated by coincidence momentum imaging. The CO+ and O+ fragment ions produced by two-body Coulomb explosion, CO22+ → CO+ + O+, exhibit asymmetric distributions along the laser polarization direction, showing that one of the two equivalent C-O bonds is selectively broken by the laser fields. At a field intensity higher than 2 × 1014 W cm-2, the largest fragment asymmetry is observed when the relative phase between the ω and 2ω laser fields is ∼0 and π. On the other hand, an increase of the asymmetry and a shift of the phase providing the largest asymmetry are observed at lower field intensities. The selective bond breaking and its dependence on the laser field intensity are discussed in terms of a mechanism involving deformation of the potential energy surfaces and electron recollision in intense laser fields.

DOI： 10.1039/c6cp07471e

Single-order laser high harmonics in XUV for ultrafast photoelectron spectroscopy of molecular wavepacket dynamics 査読有り Open Access

Fushitani, M; Hishikawa, A

STRUCTURAL DYNAMICS-US 3 巻 ( 6 ) 頁： 062602 2016年11月

担当区分：最終著者,　責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Structural Dynamics

We present applications of extreme ultraviolet (XUV) single-order laser harmonics to gas-phase ultrafast photoelectron spectroscopy. Ultrashort XUV pulses at 80 nm are obtained as the 5th order harmonics of the fundamental laser at 400 nm by using Xe or Kr as the nonlinear medium and separated from other harmonic orders by using an indium foil. The single-order laser harmonics is applied for real-time probing of vibrational wavepacket dynamics of I2 molecules in the bound and dissociating low-lying electronic states and electronic-vibrational wavepacket dynamics of highly excited Rydberg N2 molecules.

DOI： 10.1063/1.4964775

Imaging Electronic Excitation of NO by Ultrafast Laser Tunneling Ionization 査読有り

Endo, T; Matsuda, A; Fushitani, M; Yasuike, T; Tolstikhin, OI; Morishita, T; Hishikawa, A

PHYSICAL REVIEW LETTERS 116 巻 ( 16 ) 頁： 163002 2016年4月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review Letters

Tunneling-ionization imaging of photoexcitation of NO has been demonstrated by using few-cycle near-infrared intense laser pulses (8 fs, 800 nm, 1.1×1014 W/cm2). The ion image of N+ fragment ions produced by dissociative ionization of NO in the ground state, NO (X2Π,2π)→NO++e-→N++O+e-, exhibits a characteristic momentum distribution peaked at 45° with respect to the laser polarization direction. On the other hand, a broad distribution centered at ∼0° appears when the A2Σ+ (3sσ) excited state is prepared as the initial state by deep-UV photoexcitation. The observed angular distributions are in good agreement with the corresponding theoretical tunneling ionization yields, showing that the fragment anisotropy reflects changes of the highest-occupied molecular orbital by photoexcitation.

DOI： 10.1103/PhysRevLett.116.163002

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

Liu, CN; Morishita, T; Fushitani, M; Hishikawa, A

JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS 49 巻 ( 3 ) 頁： 034005 2016年2月

担当区分：最終著者記述言語：英語掲載種別：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 CO<sub>2</sub> in phase-locked two-color intense laser fields 査読有り

Endo, T; Fujise, H; Matsuda, A; Fushitani, M; Kono, H; Hishikawa, A

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

担当区分：最終著者,　責任著者記述言語：英語掲載種別：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

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

Fushitani, M; Liu, CN; Matsuda, A; Endo, T; Toida, Y; Nagasono, M; Togashi, T; Yabashi, M; Ishikawa, T; Hikosaka, Y; Morishita, T; Hishikawa, A

NATURE PHOTONICS 10 巻 ( 2 ) 頁： 102 - + 2016年2月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Nature Photonics

Coherent light-matter interaction provides powerful methods for manipulating quantum systems. Rabi oscillation is one such process. As it enables complete population transfer to a target state, it is thus routinely exploited in a variety of applications in photonics, notably quantum information processing. The extension of coherent control techniques to the multiphoton regime offers wider applicability, and access to highly excited or dipole-forbidden transition states. However, the multiphoton Rabi process is often disrupted by other competing nonlinear effects such as the a.c. Stark shift, especially at the high laser-field intensities necessary to achieve ultrafast Rabi oscillations. Here we demonstrate a new route to drive two-photon Rabi oscillations on timescales as short as tens of femtoseconds, by utilizing the strong-field phenomenon known as Freeman resonance. The scenario is not specific to atomic helium as investigated in the present study, but broadly applicable to other systems, thus opening new prospects for the ultrafast manipulation of Rydberg states.

DOI： 10.1038/NPHOTON.2015.228

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