博士（理学）, 名古屋大学

自然科学一般, 半導体、光物性、原子物理

2020年04月 - 2023年03月
名古屋大学, 大学院理学研究科 物質理学専攻（化学系）博士後期課程, 日本国

2018年04月 - 2020年03月
名古屋大学, 大学院理学研究科 物質理学専攻（化学系）, 博士前期課程, 日本国

2014年04月 - 2018年03月
名古屋大学, 理学部, 化学科, 日本国

Dissociative ionization and Coulomb explosion of CH₄ in two-color asymmetric intense laser fields
H. Hasegawa; A. Matsuda; T. Morishita; L. B. Madsen; F. Jensen; O. I. Tolstikhin; A. Hishikawa
筆頭著者, Physical Chemistry Chemical Physics, Royal Society of Chemistry (RSC), 25巻, 37号, 掲載ページ 25408-25419, 出版日 2023年09月, 査読付, Three-dimensional ion momentum imaging reveals that methane in two-color asymmetric intense laser fields has different waveform dependence for atomic and molecular hydrogen ion ejection.
研究論文（学術雑誌）

Helicity-dependent dissociative tunneling ionization of CF4 in multicycle circularly polarized intense laser fields
H. Fujise; M. Uemura; H. Hasegawa; D. Ikeya; A. Matsuda; T. Morishita; L. B. Madsen; F. Jensen; O. I. Tolstikhin; A. Hishikawa
Physical Chemistry Chemical Physics, Royal Society of Chemistry ({RSC}), 24巻, 15号, 掲載ページ 8962-8969, 出版日 2022年04月, 査読付
研究論文（学術雑誌）

Asymmetric Dissociative Tunneling Ionization of Tetrafluoromethane in omega-2 omega Intense Laser Fields
Hiroka Hasegawa; Tiffany Walmsley; Akitaka Matsuda; Toru Morishita; Lars Bojer Madsen; Frank Jensen; Oleg I. Tolstikhin; Akiyoshi Hishikawa
筆頭著者, FRONTIERS IN CHEMISTRY, FRONTIERS MEDIA SA, 10巻, 出版日 2022年04月, 査読付, Dissociative ionization of tetrafluoromethane (CF4) in linearly polarized omega-2 omega ultrashort intense laser fields (1.4 x 10(14) W/cm(2), 800 and 400 nm) has been investigated by three-dimensional momentum ion imaging. The spatial distribution of CF3+ produced by CF4 -> CF3++ F + e(-) exhibited a clear asymmetry with respect to the laser polarization direction. The degree of the asymmetry varies by the relative phase of the omega and 2 omega laser fields, showing that 1) the breaking of the four equivalent C-F bonds can be manipulated by the laser pulse shape and 2) the C-F bond directed along the larger amplitude side of the omega-2 omega electric fields tends to be broken. Weak-field asymptotic theory (WFAT) shows that the tunneling ionization from the 4t (2) second highest-occupied molecular orbital (HOMO-1) surpasses that from the 1t (1) HOMO. This predicts the enhancement of the tunneling ionization with electric fields pointing from F to C, in the direction opposite to that observed for the asymmetric fragment ejection. Possible mechanisms involved in the asymmetric dissociative ionization, such as post-ionization interactions, are discussed.
研究論文（学術雑誌）, 英語

Time-resolved shot-by-shot photoelectron spectroscopy of autoionizing Xe+ states by EUV–free-electron-laser and near-IR laser pulses
Mizuho Fushitani; Yoshitaka Kawabe; Hikaru Fujise; Makoto Yamada; Hiroka Hasegawa; Shigeki Owada; Tadashi Togashi; Kyo Nakajima; Makina Yabashi; Akitaka Matsuda; Yasumasa Hikosaka; Akiyoshi Hishikawa
Physical Review A, American Physical Society ({APS}), 104巻, 2号, 出版日 2021年08月06日, 査読付
研究論文（学術雑誌）

Angle dependence of dissociative tunneling ionization of NO in asymmetric two-color intense laser fields
Tomoyuki Endo; Hikaru Fujise; Hiroka Hasegawa; Akitaka Matsuda; Mizuho Fushitani; Oleg Tolstikhin; Toru Morishita; Akiyoshi Hishikawa
PHYSICAL REVIEW A, AMER PHYSICAL SOC, 100巻, 5号, 出版日 2019年11月, 査読付, Dissociative tunneling ionization of nitric oxide (NO) in linearly polarized phase-locked two-color femtosecond intense laser fields (45 fs, lambda = 800 and 400 nm, total field intensity I = 1 x 10(14) W/cm(2)) 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 2 pi highest 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.
研究論文（学術雑誌）, 英語

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
筆頭著者, To extend application of ω-2ω intense field reaction control to highly symmetric molecules, CF₄ was studied by three-dimensional momentum imaging. The C-F bond directed along larger side of the laser fields tends to be broken., Optica Publishing Group, 出版日 2022年07月, The International Conference on Ultrafast Phenomena (UP) 2022, 査読付

非対称強レーザー場におけるTd 対称分子の結合解離ダイナミクス
長谷川景郁; 松田晃孝; 森下 亨; 菱川明栄
日本語, 第79巻 第8号 p437-440, 日本物理学会誌, 出版日 2024年08月, 査読付

Calculation of dissociative ionization of molecules in intense laser fields
Hiroka Hasegawa
口頭発表（招待・特別）, 英語, 29th International Workshop on Theory for Attsecond Quantum Dynamics, 招待
発表日 2025年02月04日
開催期間 2025年02月03日- 2025年02月05日

Orientation dependent tunneling ionization and dissociation of methane in asymmetric two-color intense laser fields
Hiroka Hasegawa
口頭発表（招待・特別）, 英語, 15th Asian International Seminar on Atomic and Molecular Physics (AISAMP15), 招待
発表日 2024年08月22日
開催期間 2024年08月19日- 2024年08月23日

位相制御ω-2ω強レーザー場におけるCH4の解離性イオン化過程とクーロン爆発過程
長谷川景郁; 松田晃孝; 森下亨; Lars Bojer Madsen; Frank Jensen; Oleg I. Tolstikhin; 菱川明栄
口頭発表（一般）, 第78回 日本物理学会 年次大会
発表日 2023年09月17日