Author: Hayakawa, Y.
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MOP050 Development of Coherent Terahertz Wave Sources using LEBRA and KU-FEL S-band Linacs 143
 
  • N. Sei, H. Ogawa
    AIST, Tsukuba, Ibaraki, Japan
  • K. Hayakawa, Y. Hayakawa, M. Inagaki, K. Nakao, K. Nogami, T. Sakai, T. Tanaka
    LEBRA, Funabashi, Japan
  • H. Ohgaki, H. Zen
    Kyoto University, Kyoto, Japan
 
  Funding: This work is supported by the "ZE Research Program, IAE ZE27B-6".
In an infrared free-electron laser (FEL) facility using an S-band linac, a short-bunched electron beam is required to obtain a high FEL gain. Generally, the bunch length of the electron beam is compressed to 1 ps or less before interaction with the photons accumulated in the FEL resonator. This suggests that the electron beam dedicated to the FEL oscillation is suitable for generation of high-peak-power coherent radiation in terahertz (THz) wave region. Using the compressed electron beams, the coherent THz-wave sources have been developed at Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University and Kyoto University Free Electron Laser (KU-FEL). The observed powers have been higher than 100 micro-joule per macropulse*. In this presentation, the properties of the high-power coherent THz waves generated at the bending magnets will be reported.
* N. Sei et al., J. Opt. Soc. Am. B 31 (2014) 2150.
 
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TUP085 Lebra Free-Electron Laser Elicits Electrical Spikes from the Retina and Optic Nerve of the Slugs Limax Valentianus 550
 
  • F. Shishikura, K. Hayakawa, Y. Hayakawa, M. Inagaki, K. Nakao, K. Nogami, T. Sakai, T. Tanaka
    LEBRA, Funabashi, Japan
  • Y. Komatsuzaki
    Nihon University, Tokyo, Japan
 
  Since 2001, the Laboratory for Electron Beam Research and Application (LEBRA) has been providing tunable free-electron lasers (FELs) encompassing the near-IR region and some of the mid-IR region (0.9-6 microns), and generating visible wavelengths up to 400 nm by means of nonlinear optical crystals. We are investigating the efficiency of LEBRA-FELs for triggering photoreactions in living organisms. Last year we described the effects of LEBRA-FELs in controlling the photoreaction of lettuce seeds; red FEL (660 nm) and far-red FEL (740 nm) activate and inhibit germination, respectively. Here we used LEBRA-FEL to illuminate the retina of slugs (Limax valentianus), and determined which FEL wavelengths generate electrical spikes from the retina-optic nerve. Blue FEL light (wavelength: 470 nm) efficiently produced electrical spikes from the retina. The results are consistent with a previous study, where a xenon arc lamp with interference filters was used to produce monochromatic visible light. We plan to extend the wavelengths to the near- and mid-IR regions of LEBRA-FEL. We summarize our current results for the use of FEL in investigating the electrophysiology of the retina of slugs.
We thank Mr. T. Kuwabara (a graduate of Departments of Physics, College of Science and Technolgy, Nihon University) for helpful assistance.
 
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