title: Knot undulator to generate linearly polarized photons with low on-axis power density.
abstract: Heat load on beamline optics is a serious obstacle for devices designed to generate pure linearly polarized photons in third generation synchrotron radiation facilities. For permanent magnet undulators, this problem can be overcome by implementing a figure-eight design configuration. As yet there has been no good method to tackle this problem for electromagnetic elliptical undulators. Here, a novel design and operational mode is suggested, which can generate pure linearly polarized photons with very low on-axis heat load. Additionally, the minimum photon energy capability of linearly polarized photons can be significantly extended by this method.
authors.affiliation: Department of Physics, Laboratory of Advanced Materials, Fudan University, Shanghai 200433, People's Republic of China.
authors.forename: S
authors.initials: S
authors.lastname: Qiao
authors.forename: Dewei
authors.initials: D
authors.lastname: Ma
authors.forename: Donglai
authors.initials: D
authors.lastname: Feng
authors.forename: S
authors.initials: S
authors.lastname: Marks
authors.forename: R
authors.initials: R
authors.lastname: Schlueter
authors.forename: S
authors.initials: S
authors.lastname: Prestemon
authors.forename: Z
authors.initials: Z
authors.lastname: Hussain