Manipulation of Laser Distribution to Mitigate the Space-Charge Effect for Improving the Performance of a THz Coherent Undulator Radiation Source
S. Krainara, S. Chatani, H. Zen, T. Kii, H. Ohgaki, Particles, Volume 1, Pages 238-252 (2018).

Study of the Saturation of Radiation Energy Caused by the Space Charge Effect in a Compact THz Coherent Radiation Source
S. Krainara, S. Chatani, H. Zen, T. Kii, H. Ohgaki, Journal of Physics: Conference Series 1067, 032022 (2018)

Real-time Observation of Structural Change in Semi-crystalline Polymer Films through Mid-IR Transmission Spectroscopy: Determination of Instantaneous Film Temperature during Recrystallization
S. K. Maurya, T. Nakajima, K. Mizobata, H. Zen, T. Kii, and H. Ohgaki, Optics Express, Volume 26, 21615 (2018).

Mid-­Infrared Free­ Electron Laser­ Evoked Discharge of Crayfish Compound Eyes
F. Shishikura, H. Zen, K. Hayakawa, Y. Komatsuzaki, Y. Hayakawa, T. Sakai, T. Kii, H. Ohgaki, Journal of Nihon University Medical Association, Volume 77, Pages 159-164 (2018).

Visualizing Hidden Electron Trap Levels in Gd3Al2Ga3O12:Ce Crystals Using a Mid-Infrared Free Electron Laser
M. Kitaura, H. Zen, K. Kamada, S. Kurosawa, S. Watanabe, A. Ohnishi, K. Hara, Applied Physics Letters, 112, 031112 (2018).

Responses of PWO, LaBr3:Ce, and LYSO:Ce Scintillators to Single-Electron Hits of 5-40 MeV at KU-FEL
Y. Uozumi, Y. Yamaguchi, M. Fujii, H. Zen, T. Kii, H. Ohgaki, Z. Tsamalaidze, P. Evtoukhovitch, Nuclear Instruments and Methods in Physics Research A, 911, Pages 138-141 (2018).