Yusuke FURUKAWA (古川 裕介)

Offer Organization: Japan Society for the Promotion of Science, System Name: Grants-in-Aid for Scientific Research, Category: Grant-in-Aid for Scientific Research (A), Fund Type: -, Overall Grant Amount: - (direct: 31600000, indirect: 9480000)
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)).

Offer Organization: Japan Society for the Promotion of Science, System Name: Grants-in-Aid for Scientific Research, Category: Grant-in-Aid for Scientific Research (A), Fund Type: -, Overall Grant Amount: - (direct: 30000000, indirect: 9000000)
We have developed a novel broadband infrared laser pulse source, the wavelength of which spans form 1.2μm to 2.1 μm. This laser source can potentially generate an isolated attosecond pulse with the high-order harmonic generation to observe and control quantum states in atoms and molecules, even though the laser system should be improved. The preliminary study by using an existing harmonic beam line with a 12-fs Ti:sapphaire laser revealed the sub-20 fs dynamics of the nuclear wave-packet (WP) generated on the adiabatic potential of D_<2+>/H_<2+> molecule. This was the first observation the WP pumped with a sub-10 fs extreme ultraviolet pulse and probed with a vacuum ultraviolet pulse.