Studies on coherent synchrotron radiation at UVSOR-II

It is well known that 'synchrotron radiation is broadband in nature, from radio-wave to X-rays'. However, we have succeeded in producing quasi-monochromatic synchrotron radiation in a uniform magnetic field. We have developed a new method to modulate longitudinal density distribution of electron beam by using laser. We have produced sinusoidal density modulation on an electron bunch circulating in the UVSOR-II electron storage ring. We have observed that this bunch emitted quasi-monochromatic synchrotron radiation in a uniform magnetic field. It was demonstrated that, by controlling the pulse shape of the laser, we could control the radiation wavelength. The radiation mechanism was coherent synchrotron radiation. The emitted light was not only monochromatic but also coherent. In addition, the intensity was much greater than normal synchrotron radiation by many orders of magnitudes. By using this method, we can control the amplitude and the phase of synchrotron radiation. (author)