Statistical Analysis of Crossed Undulator for Polarization Control in a SASE FEL

Abstract

There is a growing interest in producing intense, coherent x-ray radiation with an adjustable and arbitrary polarization state. In this paper, we study the crossed undulator scheme (K.-J. Kim, Nucl. Instrum. Methods A {\bf 445}, 329 (2000)) for rapid polarization control in a self-amplified spontaneous emission (SASE) free electron laser (FEL). Because a SASE source is a temporally chaotic light, we perform a statistical analysis on the state of polarization using FEL theory and simulations. We show that by adding a small phase shifter and a short (about 1.3 times the FEL power gain length), $90^{\circ }$ rotated planar undulator after the main SASE planar undulator, one can obtain circularly polarized light -- with over 80% polarization -- near the FEL saturation.

arXiv comment14 pages, 4 figures

References in corpus (1)

• Optical Klystron Enhancement to SASE X-ray FELs

Cited by in corpus (10)

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• Harmonic lasing of x-ray free electron laser: on the way to smaller and cheaper
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• Simulation studies on laser pulse stability for Dalian Coherent Light Source
• FEL Polarization Control Studies on Dalian Coherent Light Source
• Polarization control of an X-ray free electron laser oscillator
• Single-shot measurement of free-electron laser polarization at SDUV-FEL