Radiation from Laser-modulated and Laser-sliced Electron Bunches in Uvsor-ii*

It was successfully demonstrated at UVSOR-II that, by using an external laser source, various micro-density structures such as a femtosecond dip or periodic modulation could be created on an electron bunch circulating in a storage ring. The bunch with femtosecond dip emitted broadband coherent synchrotron radiation. That with periodic density modulation emitted coherent and monochromatic terahertz radiation in a uniform magnetic field of a bending magnet. The results indicate that the laser modulation technique makes it possible to control the wavelength, bandwidth, amplitude, phase or number of cycles of radiation field emitted by relativistic electron bunches.