Third harmonic lasing in a storage ring free-electron laser

摘要

We report the first experimental achievement of a storage ring free-electron laser (FEL) oscillation on the third harmonic in the near-infrared region. The FEL gain was evaluated as 0.029% per mA. The measured linewidth of the third-harmonic FEL was less than that of the fundamental FEL, and the measured pulse width of the third-harmonic FEL was wider than that of the fundamental FEL. A higherharmonic FEL should be developed not only to enhance the wavelength region of the FEL but also to vary the characteristics of an FEL micropulse.