CVClient

Yoshihito Tanaka

  (田中 義人)

Profile Information

Affiliation
Prof., Graduate School of Science, University of Hyogo
Degree
博士(理学)(Jun, 1992, 東京大学)

J-GLOBAL ID
200901096887598881
researchmap Member ID
5000072608

External link

Papers

 114
  • Keisuke Kaneshima, Takumi Kyoda, Shuta Sugeta, Yoshihito Tanaka
    J. Synchrotron Rad., 31 821-828, 2024  Peer-reviewedLast author
  • Takashi Tanaka, Yuichiro Kida, Satoshi Hashimoto, Shuji Miyamoto, Tadashi Togashi, Hiromitsu Tomizawa, Aoi Gocho, Keisuke Kaneshima, Yoshihito Tanaka
    Physical Review Letters, 131(14), Oct 3, 2023  Peer-reviewed
  • Keisuke Kaneshima, Takumi Minami, Takumi Kyoda, Yoshihito Tanaka
    Optics Continuum, 1(9) 1939-1945, Aug, 2022  Peer-reviewedLast author
    Objective lenses are frequently employed in state-of-the-art ultrafast time-resolved microscopy techniques. While it enables tight spatial focusing, its dispersion causes a longer optical pulse duration. Since an objective lens is a combination of different lens materials, finding its correct dispersion can be challenging. In this paper, we propose a dispersion measurement method for an objective lens using white light interferometry. Our proposed method enables the experimental determination of the lens dispersion and improves the temporal resolution of ultrafast time-resolved microscopy techniques.
  • Takayuki Hasegawa, Masaya Marui, Yoshihito Tanaka
    Applied Physics Express, 15(5) 051001-051001, Apr, 2022  Peer-reviewedLast author
    Abstract We have investigated the dependence of terahertz wave emissions on the internal electric field in undoped GaAs/n-type GaAs epitaxial structures irradiated by ultrashort laser pulses. The undoped layer has an electric field, the strength of which was controlled by the temperature in addition to the undoped layer thickness. We observed the electric field dependence of the terahertz waveform, and the results were explained by the calculation of the transient dynamics of electrons and phonons under electric fields. Furthermore, we indicated that the terahertz amplitude can be linearly controlled by the electric field strength in a wide electric field range.
  • T. Gejo, T. Nishie, T. Nagayasu, K. Tanaka, Y. Tanaka, A. Niozu, K. Nagaya, R. Yamamura, N. Futamata, T. Suenaga, O. Takahashi, T. Togashi, S. Owada, H. Fujise, A. Verna, M. Yabashi, M. Oura
    Journal of Physics B: At. Mol. Opt. Phys., 54(14) 144004, 2021  Peer-reviewedInvited
    The dissociation and ionization dynamics of CF3I and CH3I molecules were investigated using a pump-and-probe technique that employs a soft x-ray free-electron laser (SACLA) in Japan. First, time-resolved inner-shell photoelectron spectroscopy was employed to observe the ultrafast reaction of CF3I by monitoring iodine 4d electrons. The change in the I 4d state observed in the photoelectron spectra is found to occur with a rise time τ of approximately 40 fs after a pump laser pulse, which is faster than that observed when an ultrafast gas-phase electron diffraction technique is employed. This implies that the inner-shell photoelectron spectroscopy is more sensitive to the potential surface near the Franck–Condon region. Second, a strong laser intensity at 266 nm, corresponding to a power density of 1.9 × 1014 W cm−2, can easily ionize CH3I molecules via multiphoton ionization processes, and the time dependence of the valence photoelectron spectra clearly shows that at the picosecond timescale, this pump laser pulse causes spectral peaks to shift owing to space-charge effects in response to the large amount of ions generated. Thus, the SACLA can be a useful tool to investigate not only the dynamical process of molecular dissociation but also the ionization process through the shift in the peaks of photoelectron spectra.

Misc.

 67

Books and Other Publications

 10

Presentations

 41

Research Projects

 19