Circular polarization with crossed-planar undulators in high gain FELs.
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; TRN: US0102295
- Resource Relation:
- Conference: 21st International Free Electron Laser Conference, Hamburg (DE), 08/23/1999--08/28/1999; Other Information: PBD: 31 Aug 1999
- Country of Publication:
- United States
- Language:
- English
Similar Records
Statistical Analysis of Crossed Undulator for Polarization Control in a SASE FEL
Effects of undulator interruptions on the performance of high-gain FEL amplifiers