Spatiotemporally structured synchrotron radiation

Abstract

Undulators are widely used in synchrotron light sources, which produce periodic magnetic field and make high energy electrons undulating or spiraling. Such electrons radiate electromagnetic waves which possess characteristic structures in space and time. We review our experimental results on the control of spatiotemporal structures of UV/EUV light wave packets emitted from relativistic electrons. From a device called helical undulators, optical vortex beam which has spiral phase structure can be generated. By using a combination of such undulators, optical vector beams can be synthesized. The radiation wave packets emitted from undulator possess ultrashort sinusoidal waveform with the number of cycles exactly same as that of the undulator magnetic periods. Those from two undulators arranged in tandem possess double-pulse time structure with attosecond precision. Their applications to coherent control of atoms and ultrafast spectroscopy were successfully demonstrated.