Observation of mutual coherency of spontaneous radiation from two undulators separated by achromatic bend

The mutual coherency of spontaneous radiation from two undulators separated by an achromatic bend was observed. An updated magnetic system with an optical klystron was implemented for this experiment. The experiments confirm theoretical expectations. The possible use of a similar technique for efficient power extraction from high-power free-electron lasers (FELs) is discussed. This experiment shows the importance of bend achromaticity for mutual coherency of spontaneous radiation from two undulators.<
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