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RIKEN Center for Emergent Matter Science Emergent Spectroscopy Research Unit

Unit Leader: Youtarou Takahashi (Ph.D.)

Research Summary

Youtarou  Takahashi(Ph.D.)

Optical phenomena are critical for understanding the physical properties of matter, while the material with a particular property provides the novel optical phenomena. Our current research interests focus on the novel optical phenomena driven by the strong coupling between the dielectric and magnetic properties in matter, the optical control of the state of matter and the conduction electron dynamics in the strongly correlated electron system. The dynamical responses of the strongly correlated systems are investigated by the state-of-the-art laser spectroscopy including the terahertz and ultrafast spectroscopy.

Main Research Fields

  • Mathematical & Physical Sciences

Related Research Fields

  • Interdisciplinary Science & Engineering


  • magnetism
  • multiferroics
  • Nonreciprocal optics
  • terahertz

Selected Publications

  • 1.Kurumaji, T. Takahashi, Y. Fujioka, J. Masuda, R. Shishikura, H. Ishiwata S. and Tokura, Y.:
    "Electromagnon resonance in a collinear spin state of the polar antiferromagnet Fe2Mo3O8"
    PHYSICAL REVIEW B 95, 020405(R) (2017)
  • 2.Narita, H. Tokunaga, Y. Kikkawa, A. Taguchi, Y. Tokura, Y. and Takahashi, Y.:
    "Observation of nonreciprocal directional dichroism via electromagnon resonance in a chiral-lattice helimagnet Ba3NbFe3Si2O14"
    PHYSICAL REVIEW B 94, 094433 (2016)
  • 3.Okada, K. N. Takahashi, Y. Mogi, M. Yoshimi, R. Tsukazaki, A. Takahashi, Kei S. Ogawa, N. Kawasaki, M. and Tokura, Y.:
    "Terahertz spectroscopy on Faraday and Kerr rotations in a quantum anomalous Hall state"
    Nature Communications 7:12245 (2016)
  • 4.Takahashi, Y. Kibayashi, S. Kaneko, Y. and Tokura, Y.:
    "Versatile optical magnetoelectric effects by electromagnons in MnWO4 with canted spin-spiral plane"
    PHYSICAL REVIEW B 93, 180404(R) (2016)
  • 5.Kibayashi, S. Takahashi, Y. Seki, S. and Tokura, Y.:
    "Magnetochiral dichroism resonant with electromagnons in a helimagnet"
    Nature Communications 5:4583 (2014)
  • 6.Takahashi, Y., Chakraverty, S., Kawasaki, M., Hwang, H. Y., and Tokura, Y.:
    "In-plane terahertz response of thin film Sr2RuO4"
    Phys. Rev. B89, 165116 (2014).
  • 7.Ueda, K., Fujioka, J., Takahashi, Y., Suzuki, T., Ishiwata, S., Taguchi, Y., Kawasaki, M. and Tokura, Y.:
    "Anomalous domain-wall conductance in Pyrochlore-type Nd2Ir2O7 on the verge of metal-insulator transition"
    Phys. Rev. B89, 075127 (2014).
  • 8.Takahashi, Y., Yamasaki, Y., and Tokura, Y.:
    "Terahertz Magnetoelectric Resonance Enhanced by Mutual Coupling of Electromagnons"
    Phys. Rev. Lett.111.037204 (2013).
  • 9.Ueda, K., Fujioka, J., Takahashi, Y., Suzuki, T., Ishiwata, S., Taguchi, Y., and Tokura, Y.:
    "Variation of Charge Dynamics in the Course of Metal-Insulator Transition for Pyrochlore-Type Nd2Ir2O7"
    Phys. Rev. Lett.109.136402 (2012).
  • 10.Takahashi, Y., Shimano, R., Kaneko, Y., Murakawa, H., and Tokura, Y.:
    "Magnetoelectric resonance with electromagnon in a perovskite helimagnet"
    Nature Physics 8, 121-125 (2012).

Recent Research Results

Related Links

Lab Members

Principal investigator

Youtarou Takahashi
Unit Leader

Core members

Yoshihiro Okamura
Visiting Scientist

Contact Information

Quantum-Phase Electronics Center,
School of Engineering,
The University of Tokyo,
7-3-1 Hongo, Bunkyo-ku,
113-8656, Japan
Email: youtarou.takahashi [at] riken.jp