This paper presents an overview of optical, thermal, and mechanical problems encountered with optical elements in beams of synchrotron-radiation (SR) emitted by electron "sidewinders" such as wigglers, undulators, and free-electron lasers (FELs). Perhaps the most challenging problem is the management of the high-power densities from wigglers without degradation of the optical quality of the beam. Another challenging problem is the reduction of near-specular scattering by surfce microroughness on the mirrors. Near-specular scattering becomes more important as the degree of coherence and collimation to be maintained increases from bend-magnet SR to undulator and FEL radiation. It is emphasized that the surface autocovariance length of the mirror is the determiner of the angular distribution of scattering, and that very long autocovariance lengths are required for highly coherent SR beams.
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