The generation of frequency-tunable, narrow-bandwidth and carrier-envelope-phase stable THz pulses with fields in the MV/cm regime that can be appropriately timed to the femtosecond X-ray pulses from free-electron-lasers is of highest scientific interest. It will enable to follow the electronic and structural dynamics stimulated by (non)linear selective excitations of matter on few femtosecond time and {\AA}ngstrom length scales. In this article, a scheme based on superradiant undulator radiation generated just after the XFEL is proposed. The concept utilizes cutting edge superconducting undulator technology and provides THz pulses in a frequency range between 3 and 30 THz with exceptional THz pulse energies. Relevant aspects for realization and operation are discussed point by point on the example of the European XFEL.
@article{arxiv.1803.05323,
title = {Superradiant Undulator Radiation for Selective THz Control Experiments at XFELs},
author = {Takanori Tanikawa and Suren Karabekyan and Sergey Kovalev and Sara Casalbuoni and Vivek Asgekar and Svitozar Serkez and Michael Gensch and Gianluca Geloni},
journal= {arXiv preprint arXiv:1803.05323},
year = {2019}
}