Seifert, T., Jaiswal, S., Martens, U., Hannegan, J., Braun, L., Maldonado, P., et al. (2016). Efficient metallic spintronic emitters of ultrabroadband terahertz radiation. Nature Photonics, 10(7), 483-488. doi:10.1038/NPHOTON.2016.91.