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Observation of Optical Amplification Excited by Traveling Electron Beam

The amplification of optical light excited by a traveling electron in a vacuum environment was first observed in the near-infrared optical region as that in a Cherenkov-type amplifier. Light with a wavelength of 1.5 µm propagated in a Si–SiO2 dielectric waveguide. The accelerated voltage of the electron beam for the amplification was approximately 42 kV. The dispersion relation between wavelength and acceleration voltage well agreed with theoretically calculated results.