%0 Journal Article
%T Efficient metallic spintronic emitters of ultrabroadband terahertz radiation
%A T. Seifert
%A S. Jaiswal
%A U. Martens
%A J. Hannegan
%A L. Braun
%A P. Maldonado
%A F. Freimuth
%A A. Kronenberg
%A J. Henrizi
%A I. Radu
%A E. Beaurepaire
%A Y. Mokrousov
%A P. M. Oppeneer
%A M. Jourdan
%A G. Jakob
%A D. Turchinovich
%A L. M. Hayden
%A M. Wolf
%A M. M¨¹nzenberg
%A M. Kl£¿ui
%A T. Kampfrath
%J Physics
%D 2015
%I arXiv
%X Terahertz electromagnetic radiation is extremely useful for numerous applications such as imaging and spectroscopy. Therefore, it is highly desirable to have an efficient table-top emitter covering the 1-to-30-THz window whilst being driven by a low-cost, low-power femtosecond laser oscillator. So far, all solid-state emitters solely exploit physics related to the electron charge and deliver emission spectra with substantial gaps. Here, we take advantage of the electron spin to realize a conceptually new terahertz source based on tailored fundamental spintronic/photonic phenomena in magnetic metal multilayers: a spin-dependent generalization of the photo-Dember effect, the inverse spin-Hall effect and a broadband Fabry-P\'erot resonance. Guided by an analytical model, such spintronic route offers unique possibilities for systematic optimization. We find that a 5.8-nm-thick W/CoFeB/Pt trilayer generates ultrashort THz pulses fully covering the 1-to-30-THz range. Our novel source outperforms standard emitters such as ZnTe(110) crystals in terms of bandwidth, conversion efficiency, flexibility, scalability and cost.
%U http://arxiv.org/abs/1510.03729v1