Synchrotron radiation from laser-accelerated monoenergetic electrons

In this paper, we report on the generation of incoherent synchrotron radiation in the visible spectral range which is produced by laser-accelerated electrons with 55-75-MeV energy as they propagate through an undulator. Simultaneous detection of electron and photon spectra allows for precise comparison between experimental results and undulator theory. First- and second-order undulator radiation was detected. The agreement between experiment and theory and the exclusion of other effects proves that the observed radiation is generated in the undulator. Beyond that, this experiment introduces laser-accelerated electrons into the radio-frequency accelerator domain of synchrotron light sources. This marks a noticeable step toward a new, compact, and brilliant short-wavelength light source.