THD04
USTC/NSRL, Hefei, Anhui, People’s Republic of China
We report a laser-driven undulator for developing compact ultraviolet-to-X free-electron lasers (FELs), which overcomes the main disadvantages of previous optical and magnetic undulators. It uses an array of transverse-polarized laser beams with alternated phases to provide the periodic deflecting fields. The pulse-front tilt is applied to free the undulating period from the laser wavelength. The transverse electric field of laser is to deflect the electrons in the vacuum, which greatly increases the efficiency and the achievable deflecting forces since it avoids the breakdown of medium. The ultraviolet-to-X FEL with a desirable undulator strength can be achieved by lasers with intensities being orders of magnitude less than that in previous optical undulator, and by electrons with energies being remarkably less than that of magnetic undulator. Thus, it affords a promising way for developing the ultra-compact and powerful FELs.
