Study on attosecond quantum wavepacket dynamics

2018 Fiscal Year Final Research Report

• Project/Area Number: 26247068
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Atomic/Molecular/Quantum electronics
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Nabekawa Yasuo 国立研究開発法人理化学研究所, 光量子工学研究センター, 専任研究員 (90344051)
• Research Collaborator: Takahashi Eiji J. (80360577) ; Furukawa Yusuke (20464232) ; Okino Tomoya (40431895) ; Kanda Natsuki (60631778) ; Abdolreza Amani (80611491) ; Lin Yu-Chieh (00752073)
• Project Period (FY): 2014-04-01 – 2019-03-31
• Keywords: アト秒科学 / 高次高調波 / 非線形光学 / 量子制御 / 極端紫外 / 真空紫外 / フェムト秒レーザー

Outline of Final Research Achievements

We could reveal ultrafast dynamics of simple molecules and succeed in controlling the reaction pathways using a pair of attosecond pulse train (APT). First, we discovered the `~1-fs settling time needed for creating a vibrational wavepacket in H2+ molecule. Two-dimensional spectrogram, which was a record of the kinetic energy release (KER) of H+ fragment with scanning delay between two APTs, was analyzed by the frequency-resolved optical gating technique. We found the initial delays between the vibrational wavefunctions forming the wavepacket, which can be interpreted as the settling time (Nat. Commun. 6:8197 (2015).). Second, we found an attosecond electronic wavepacket generated in N2 and N2+ molecules (Sci. Adv. 1, e1500356 (2015).). Third, we controlled the dissociation pathways of H2+ by utilizing the ultrafast vibrational motion. Only 8-fs delay difference of the control APT switched the dissociation pathway of 2pσu state to that of 2pπu state (Nat. Commun. 7:12835(2016)).

Free Research Field

量子エレクトロニクス

Academic Significance and Societal Importance of the Research Achievements

研究代表者の知る限り、アト秒パルス誘起による量子波束制御の研究例はない。従って、アト秒パルスを超高速量子ダイナミックスを観測するためのプローブのみならず、励起や制御にも用いることができるということを実証した点で本研究の学術的な意義は大変大きい。これはアト秒パルスの高い光子エネルギーと広い周波数帯域という利点を複数の量子準位の励起に活かしたことによるものである。今後は、制御光とプローブ光を独立に制御することで、より複雑な量子波束制御への展開が期待できる。