Circular polarization with crossed-planar undulators in high gain FELs.

Conference · Tue Aug 31 04:00:00 EDT 1999

OSTI ID:11933

Kim, K -J

We propose a crossed undulator configuration for a high-gain free-electron laser to allow versatile polarization control. This configuration consists of a long (saturation length) planar undulator, a dispersive section, and a short (a few gain lengths) planar undulator oriented perpendicular to the first one. In the first undulator, a radiation component linearly polarized in the x-direction is amplified to saturation. In the second undulator, the x-polarized component propagates freely, while a new component, polarized in the y-direction, is generated and reaches saturation in a few gain lengths. By adjusting the strength of the dispersive section, the relative phase of two radiation components can be adjusted to obtain a suitable polarization for the total radiation field, including the circular polarization. The operating principle of the high-gain crossed undulator, which is quite different from that of the crossed undulator for spontaneous radiation, is illustrated in terms of 1-D FEL theory.

• Research Organization: Argonne National Lab., IL (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 11933
• Report Number(s): ANL/ASD/CP-99801
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
DESIGN
FREE ELECTRON LASERS
POLARIZATION
PROCESS CONTROL
SATURATION
WIGGLER MAGNETS