Efficient metallic spintronic emitters of ultrabroadband terahertz radiation
2016 (English)In: Nature Photonics, ISSN 1749-4885, E-ISSN 1749-4893, Vol. 10, no 7, 483-+ p.Article in journal (Refereed) PublishedText
Terahertz electromagnetic radiation is extremely useful for numerous applications, including imaging and spectroscopy. It is thus highly desirable to have an efficient table-top emitter covering the 1-30 THz window that is 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 that relies on three tailored fundamental spintronic and photonic phenomena in magnetic metal multilayers: ultrafast photoinduced spin currents, the inverse spin-Hall effect and a broadband Fabry-Perot resonance. Guided by an analytical model, this spintronic route offers unique possibilities for systematic optimization. We find that a 5.8-nm-thick W/CoFeB/Pt trilayer generates ultrashort pulses fully covering the 1-30 THz range. Our novel source outperforms laser-oscillator-driven emitters such as ZnTe(110) crystals in terms of bandwidth, terahertz field amplitude, flexibility, scalability and cost.
Place, publisher, year, edition, pages
2016. Vol. 10, no 7, 483-+ p.
Atom and Molecular Physics and Optics
IdentifiersURN: urn:nbn:se:uu:diva-299854DOI: 10.1038/NPHOTON.2016.91ISI: 000378839600015OAI: oai:DiVA.org:uu-299854DiVA: diva2:950272
FunderGerman Research Foundation (DFG), SFB TRR 173/Spin+XEU, European Research Council, 681917; 280879; 608031; 334324; 281043Swedish Research CouncilKnut and Alice Wallenberg Foundation