研究者詳細 - 伏谷　瑞穂

論文 - 伏谷　瑞穂

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Wave-packet manipulation of He Rydberg states by a seeded free-electron laser 査読有り

Dumergue M., Carpeggiani P.A., Csizmadia T., Danailov M., Demidovich A., De Ninno G., Di Fraia M., Eng-Johnsson P., Ertel D., Fujise H., Fushitani M., Giannessi L., Gopalakrishna H.N., Hishikawa A., Ibrahim H., Kühn S., Légaré F., Luo Y., Maroju P.K., Mauritsson J., Moioli M., Olofsson A., Peschel J., Plekan O., Pratt S.T., Raimondi L., Ribič P.R., Saito S., Sansone G., Shah R., Simpson E.R., You D., Zangrando M., Callegari C., Ueda K., Prince K.C.

Physical Review Research 6 巻 ( 4 ) 頁： 043323 2024年12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：Physical Review Research

We report a two-dimensional pump-control-probe spectroscopic study of the dynamics of singly excited He Rydberg-state wave packets with a seeded extreme ultraviolet (XUV) free-electron laser (FEL) source. A pair of coherent XUV pulses, defined by their coarse time separation and relative phase, created and manipulated the wave packets. The He atoms were postionized by infrared (IR) pulses, and the ion yield was measured as a function of XUV phase and IR arrival time. We tagged and sorted the relative phase of the XUV pulse pair on a single-shot basis by fitting each FEL spectrum with a suitable function that accounts for nonidealities of the XUV pulse pairs, associated with the seeding process; more generally, the fit returns the time-dependent electric field of the FEL spectra. The experimental two-dimensional maps of ion yields, measured as a function of IR (probe) delay and of XUV (pump-control) phase, were compared with the solution of the first-order time-dependent Schrödinger equation for this field. Despite the fact that the experimental conditions imply strong excitation, beyond the approximations of first-order perturbation theory, the simulated map satisfactorily reproduces the experimental one for temporally well-separated pulses. We show that by selecting data at appropriate values of pump-control phase, we enhance or suppress the amplitude of chosen wave-packet components consisting of two or more Rydberg states. When the temporal overlap of the pulse pair cannot be neglected, the phase reconstruction is underdetermined, and we provide a simplified comparison between data and simulations.

DOI： 10.1103/physrevresearch.6.043323

Scopus

その他リンク： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevResearch.6.043323/fulltext

State-selective dissociative double ionization of CH3I and CH2I2 via I 4d core-hole states studied by multi-electron–ion coincidence spectroscopy 査読有り

Mizuho Fushitani, Yasumasa Hikosaka, Motomichi Tashiro, Akiyoshi Hishikawa

The Journal of Chemical Physics 160 巻 ( 17 ) 頁： 174307 2024年5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：Journal of Chemical Physics

The dissociative double ionization of CH3I and CH2I2 irradiated with extreme ultraviolet light at hv = 100 eV is investigated by multi-electron-ion coincidence spectroscopy using a magnetic bottle type electron spectrometer. The spin-orbit state-resolved Auger electron spectra for the I 4d core-hole states, (I 4d3/2)−1 and (I 4d5/2)−1, provide clear identifications of electronic states of CH3I2+ and CH2I22+. The dominant ion species produced after the double ionization correlate with the Auger electron energy, showing that different fragmentation pathways are open depending on the electronic states populated by the Auger decay. Theoretical calculations are performed to understand the fragmentation from the doubly charged states and the observed spin-orbit specificity in the Auger decay.

DOI： 10.1063/5.0204769

Scopus

Wave packet dynamics and control in excited states of molecular nitrogen 査読有り国際共著国際誌

Fushitani M., Fujise H., Hishikawa A., You D., Saito S., Luo Y., Ueda K., Ibrahim H., Légaré F., Pratt S.T., Eng-Johnsson P., Mauritsson J., Olofsson A., Peschel J., Simpson E.R., Carpeggiani P.A., Ertel D., Maroju P.K., Moioli M., Sansone G., Shah R., Csizmadia T., Dumergue M., Gopalakrishna H.N., Kühn S., Callegari C., Danailov M., Demidovich A., Raimondi L., Zangrando M., De Ninno G., Di Fraia M., Giannessi L., Plekan O., Ribic P.R., Prince K.C.

Journal of Chemical Physics 160 巻 ( 10 ) 頁： 104203 2024年3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：Journal of Chemical Physics

Wave packet interferometry with vacuum ultraviolet light has been used to probe a complex region of the electronic spectrum of molecular nitrogen, N2. Wave packets of Rydberg and valence states were excited by using double pulses of vacuum ultraviolet (VUV), free-electron-laser (FEL) light. These wave packets were composed of contributions from multiple electronic states with a moderate principal quantum number (n ∼ 4-9) and a range of vibrational and rotational quantum numbers. The phase relationship of the two FEL pulses varied in time, but as demonstrated previously, a shot-by-shot analysis allows the spectra to be sorted according to the phase between the two pulses. The wave packets were probed by angle-resolved photoionization using an infrared pulse with a variable delay after the pair of excitation pulses. The photoelectron branching fractions and angular distributions display oscillations that depend on both the time delays and the relative phases of the VUV pulses. The combination of frequency, time delay, and phase selection provides significant control over the ionization process and ultimately improves the ability to analyze and assign complex molecular spectra.

DOI： 10.1063/5.0188182

Scopus

Imaging Ultrafast Dissociation Dynamics: OCS & Roaming in Formaldehyde Open Access

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

Springer Proceedings in Physics 300 巻頁： 75 - 82 2024年

出版者・発行元：Springer Proceedings in Physics

Upon photoexcitation, molecules break apart, following different dissociation reactions. We can image these dissociation pathways using Coulomb explosion imaging (CEI) and sometimes we can control them using asymmetric laser fields. In the formaldehyde molecule, we can see fragments following the direct, conventional dissociation path, as well as fragments deviating from this minimum energy path. So-called roaming fragments or “roamers” explore the potential energy landscape in a statistical manner and could be directly captured in real-time, despite the signal’s statistical character. This is possible due to the single-molecule sensitivity of CEI and we could show that the onset of roaming occurs actually several orders of magnitude earlier than previously expected. In the polar molecule OCS we go one step further by controlling the fragmentation process using two-color asymmetric laser fields. In addition to expected direct ionization effects, we also see post-ionization contributions, which are usually not visible in heavy polar molecules. We thus show in two different examples that CEI provides the means to extract new, unexpected pathways, which would otherwise remain hidden underneath a strong background.

DOI： 10.1007/978-3-031-47938-0_8

Open Access

Scopus

Capturing transient core-to-core resonances in Kr in intense extreme-ultraviolet laser fields by electron-ion coincidence spectroscopy 査読有り

Mizuho Fushitani, Makoto Yamada, Hikaru Fujise, Shigeki Owada, Tadashi Togashi, Kyo Nakajima, Makina Yabashi, Akitaka Matsuda, Yasumasa Hikosaka, Akiyoshi Hishikawa

Physical Review A (Letter) 107 巻 ( 2 ) 頁： L021101 2023年2月

Imaging and Controlling ultrafast Dissociation Dynamics; from conventional to surprising paths

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

Proceedings of SPIE - The International Society for Optical Engineering 12419 巻 2023年

出版者・発行元：Proceedings of SPIE - The International Society for Optical Engineering

Upon photo-excitation of a molecule it will break apart. We can see fragments following direct, conventional dissociation paths, as well as fragments deviating from this minimum energy path. The latter are called roaming fragments and explore the potential energy landscape in a statistical manner. Dissociating and roaming fragments are directly captured using Coulomb explosion imaging (CEI) and individual pathways are distinguished based on state-of-the-art theory analysis.

DOI： 10.1117/12.2649247

Scopus

Electronic relaxation and dissociation dynamics in formaldehyde: Pump wavelength dependence 査読有り

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

Physical Chemistry Chemical Physics 24 巻 ( 3 ) 頁： 1779 - 1786 2022年

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 Chemistry Chemical Physics

The effect of the incident UV pump wavelength on the subsequent excited state dynamics, electronic relaxation, and ultimate dissociation of formaldehyde is studied using first principles simulation and Coulomb explosion imaging (CEI) experiments. Transitions in a vibronic progression in the Ã ← X absorption band are systematically prepared using a tunable UV source which generates pulses centered at 304, 314, 329, and 337 nm. We find, both via ab initio simulation and experimental results, that the rate of excited state decay and subsequent dissociation displays a prominent dependence on which vibronic transition in the absorption band is prepared by the pump. Our simulations predict that nonadiabatic transition rates and dissociation yields will increase by a factor of >100 as the pump wavelength is decreased from 337 to 304 nm. The experimental results and theoretical simulations are in broad agreement and both indicate that the dissociation rate plateaus rapidly after ≈2 ps following an ultrafast sub-ps rise. This journal is

DOI： 10.1039/d1cp04264e

Scopus

Roaming in Formaldehyde – and how to get there

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

Optics InfoBase Conference Papers 2022年

Electron-ion Coincidence Imaging of O<inf>2</inf> in Intense Laser Fields with Additional Dissociation Pulses

Ikeya D., Matsuda A., Fushitani M., Hishikawa A.

Optics InfoBase Conference Papers 2022年

Time-resolved photoelectron imaging of complex resonances in molecular nitrogen 査読有り

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

Journal of Chemical Physics 154 巻 ( 14 ) 頁： 144305 2021年4月

担当区分：筆頭著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：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

Scopus

PubMed

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

Endo Tomoyuki, Neville Simon P., Wanie Vincent, Beaulieu Samuel, Qu Chen, Deschamps Jude, Lassonde Philippe, Schmidt Bruno E., Fujise Hikaru, Fushitani Mizuho, Hishikawa Akiyoshi, Houston Paul L., Bowman Joel M., Schuurman Michael S., Legare Francois, Ibrahim Heide

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

Web of Science

Scopus

PubMed

Multielectron-Ion Coincidence Spectroscopy of Xe in Extreme Ultraviolet Laser Fields: Nonlinear Multiple Ionization via Double Core-Hole States

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

記述言語：日本語出版者・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

Web of Science

Scopus

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

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

Phys. Rev. Lett. 124 巻 ( 19 ) 頁： 193201 2020年5月

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

Fushitani M., Liu C. -N., 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：筆頭著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：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

Web of Science

Scopus

Determination of absolute cross-sections of nonresonant EUV-UV two-color two-photon ionization of he

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

Optics InfoBase Conference Papers 2014年

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

Single-shot photoelectron spectroscopy was performed for nonresonant EUV-UV twocolor two-photon ionization of He. From data analysis on the shot-by-shot basis, the absolute cross-section was determined to be σ(2)(597nm, 268nm) = 4.1(6)×10-52 cm4 s. © 2014 OSA.

DOI： 10.1364/up.2014.08.tue.p2.5

Scopus

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

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

Ultrafast photoelectron spectroscopy of electron-ion wave packets in Rydberg N<inf>2</inf>

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

Optics InfoBase Conference Papers 2014年

Ultrafast coulomb explosion of formaldehyde in 7 and 35 fs intense laser fields studied by triple ion-coincidence momentum imaging

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

Optics InfoBase Conference Papers 2014年

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

Fushitani Mizuho, Matsuda Akitaka, Hishikawa Akiyoshi

JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 184 巻 ( 11-12 ) 頁： 561 - 568 2012年1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

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 1Π u) → Br( 2P 3/2) + Br( 2P 3/2), are presented. © 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.elspec.2011.10.002

Web of Science

Scopus

Applications of pump-probe spectroscopy 査読有り

Mizuho Fushitani

Annual Reports on the Progress of Chemistry - Section C 104 巻頁： 272 - 297 2008年

掲載種別：研究論文（学術雑誌）

This review outlines advances that have been made in recent years (2005-2007) in the study of ultrafast dynamics occurring in physical, chemical and biological research fields by using pump-probe techniques. Special emphasis is placed on coherent phenomena in materials and experimental achievements of coherent control of wave packets dynamics. After a brief theoretical description of pump-probe methods, an overview of nuclear and electronic coherences appearing in pump-probe spectroscopy is presented. Some of the highlights include molecular alignments, wave packet interferometry, hydrogen migration, and attosecond electron dynamics. © 2008 The Royal Society of Chemistry.

DOI： 10.1039/b703983m

Scopus

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