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RIKEN Center for Advanced Photonics Ultrafast Coherent Soft X-ray Photonics Research Team

Team Leader: Eiji J. Takahashi (D. Eng.)

Research Summary

Eiji J. Takahashi(D. Eng.)

Laser is the ultimate light source created by mankind, and it has become an indispensable tool for our social life. In this laboratory, our main goal is to create an unexplored ultrafast laser by using the extreme nature of laser such as ultrashort pulse, super broadband, high power, and so on. Specifically, we are developing a high-power a few-cycle laser source and using it to develop a novel laser source with full coherence in the soft x-ray region and a pulse width of the attosecond region. We extend the frontier of laser science through the development of novel laser sources.

Main Research Fields

  • Engineering

Related Research Fields

  • Complex Systems
  • Interdisciplinary Science & Engineering
  • Optical engineering and photon science-related
  • Quantum beam science-related
  • Optical properties of condensed matter and atomic physics-related


  • High-power a few-cycle laser
  • Coherent soft x-ray
  • Quantum beam
  • Strong-field physics
  • Ultrafast soft x-ray photonics

Selected Publications

  • 1. Lu. X. and Takahashi, E.J.:
    "Dual-chirped optical parametric amplification of high-energy single-cycle laser pulses"
    Nature Photonics 18, 99-106 (2024).
  • 2. Bing, X., Midorikawa, K., and Takahashi, E.J.:
    "Gigawatt-class, tabletop, isolated-attosecond-pulse light source"
    Optica 9, 360-363 (2022).
  • 3. Lu, X., Bing, X., Ishii, N., Itatani, J., Midorikawa, and Takahashi, E.J.:
    "100-mJ class, sub-two-cycle, carrier-envelope phase-stable dual-chirped optical parametric amplification"
    Opt. Lett. 47, 3371-3374 (2022).
  • 4. Bing, X., Tamaru, Y., Fu, Y., Yuan, H., Lan, P., Mucke, O.D., Suda, A., Midorikawa, K., and Takahashi, E.J.:
    "A Custom-Tailored Multi-TW Optical Electric Field for Gigawatt Soft-X-Ray Isolated Attosecond Pulses."
    Ultrafast Science 2021, 1-13 (2021).
  • 5. Bing, X., Tamaru, Y., Fu, Y., Yuan, H., Lan, P., Mucke, O.D., Suda, A., Midorikawa, K., and Takahashi, E.J.:
    "Fully stabilized multi-TW optical waveform synthesizer: Toward gigawatt isolated attosecond pulses"
    Science Advances, 6: eaay2802. (2020).
  • 6. Yuxi, F., Nishimura, K., Shao, R., Suda, A., Midorikawa, K., Lan, P., and Takahashi, E.J.:
    "High efficiency ultrafast water-window harmonic generation for single-shot soft X-ray spectroscopy"
    Communications Physics, 3: 92. (2020).
  • 7. Lu, X., Nishimura, K., Suda, A., Midorikawa, K., Fu, Y., and Takahashi, E.J.:
    "Optimization of a multi-TW few-cycle 17-μm source based on Type-I BBO dual-chirped optical parametric amplification"
    Optics Express, 28: 15138-47. (2020).
  • 8. Yuxi, F., Midorikawa, K., and Takahashi, E.J.:
    "Dual-Chirped Optical Parametric Application: A Method for Generating Super-Intense Mid-Infrared Few-Cycle Pulses"
    IEEE Journal of Selected Topics in Quantum Electronics 25, 1-13 (2019).
  • 9. Yuxi, F., Midorikawa, K., and Takahashi, E.J.:
    "Towards a petawatt-class few-cycle infrared laser system via dual-chirped optical parametric amplification"
    Scientific Reports, 8: 7692. (2018).
  • 10. Yuxi, F., Bing, X., Midorikawa, K., and Takahashi, E.J.:
    "TW-scale mid-infrared pulses near 3.3 μm directly generated by dual-chirped optical parametric amplification"
    Applied Physics Letters, 112: 241105. (2018).

Recent Research Results

Related Links

Lab Members

Principal investigator

Eiji J. Takahashi
Team Leader

Core members

Yasuo Nabekawa
Senior Research Scientist
Natsuki Kanda
Research Scientist
Kotaro Imasaka
Postdoctoral Researcher
Kaito Nishimiya
Postdoctoral Researcher
Rambabu Rajpoot
Postdoctoral Researcher
Dai Ikeda
Special Postdoctoral Researcher
Hushan Wang
Visiting Scientist
Dianhong Dong
International Program Associate
Minshuang Xia
International Program Associate

Contact Information

W507, 5F, Cooperation Center,
2-1 Hirosawa,
Wako, Saitama
351-0198, Japan
Email: ufsxp-info [at] ml.riken.jp