Ultrafast Coherent Soft X-ray Photonics Research Team

Team Leader

Eiji J. Takahashi

D. Eng.

Photo: Eiji Takahashi


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

2-1 Hirosawa, Wako, Saitama 351-0198 Japan


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 novel laser source with full coherence in the soft x-ray region and a pulse width of attosecond region. We extend the frontier of laser science through the development of novel laser sources.


Interdisciplinary Science and Engineering, Engineering, Complex systems


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


  1. High-intensity single-cycle laser pulse
  2. High-power coherent soft x-ray attosecond pulse
  3. Ultrafast soft x-ray science
  4. Next-generation quantum beam sources
Research image

Emission from the generating medium of coherent soft x-ray

Selected Publications

  1. Bing, X., Tamaru, Y., Fu, Y., Yuan, H., Lan, P., Mücke, 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: 9828026 (2021).
  2. Nishimura, K., Yuxi, F., Suda, A., Midorikawa, K., and Takahashi, E.J.: “Apparatus for generation of nanojoule-class water-window high-order harmonics” , Rev. Sci. Instrum. 92: 063001 (2021).
  3. Bing, X., Tamaru, Y., Fu, Y., Yuan, H., Lan, P., Mücke, 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).
  4. 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).
  5. 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).



Eiji J. TakahashiTeam Leader
Yasuo NabekawaSenior Research Scientist
Lu XuPostdoctoral Researcher
Giang Nahan TranPostdoctoral Researcher