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Efficient metallic spintronic emitters of ultrabroadband terahertz radiation

Nature Photonics volume 10, pages 483–488 (2016)Cite this article

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Abstract

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–Pérot 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.

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Figure 1: Metallic spintronic terahertz emitter.
Figure 2: Impact of the NM material.
Figure 3: Impact of stack geometry on emitter performance.
Figure 4: Spintronic emitter performance and spectroscopic application.

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References

  1. Ferguson, B. & Zhang, X. Materials for terahertz science and technology. Nature Mater. 1, 26–33 (2002).

    Article  ADS  Google Scholar 

  2. Tonouchi, M. Cutting-edge terahertz technology. Nature Photon. 1, 97–105 (2007).

    Article  ADS  Google Scholar 

  3. Ulbricht, R., Hendry, E., Shan, J., Heinz, T. & Bonn, M. Carrier dynamics in semiconductors studied with time-resolved terahertz spectroscopy. Rev. Mod. Phys. 83, 543–586 (2011).

    Article  ADS  Google Scholar 

  4. Kampfrath, T., Tanaka, K. & Nelson, K. Resonant and nonresonant control over matter and light by intense terahertz transients. Nature Photon. 7, 680–690 (2013).

    Article  ADS  Google Scholar 

  5. Chan, W., Deibel, J. & Mittleman, D. Imaging with terahertz radiation. Rep. Prog. Phys. 70, 1325–1379 (2007).

    Article  ADS  Google Scholar 

  6. Cocker, T. L. et al. An ultrafast terahertz scanning tunnelling microscope. Nature Photon. 7, 620–625 (2013).

    Article  ADS  Google Scholar 

  7. Sano, Y. et al. Imaging molecular adsorption and desorption dynamics on graphene using terahertz emission spectroscopy. Sci. Rep. 4, 6046 (2014).

    Article  Google Scholar 

  8. Zeitler, J. et al. Terahertz pulsed spectroscopy and imaging in the pharmaceutical setting—a review. J. Pharm. Pharmacol. 59, 209–223 (2007).

    Article  Google Scholar 

  9. Reimann, K. Table-top sources of ultrashort THz pulses. Rep. Prog. Phys. 70, 1597–1632 (2007).

    Article  ADS  Google Scholar 

  10. Blanchard, F. et al. Generation of intense terahertz radiation via optical methods. IEEE J. Sel. Top. Quantum Electron. 17, 5–16 (2011).

    Article  ADS  Google Scholar 

  11. Rice, A. et al. Terahertz optical rectification from 〈110〉 zinc-blende crystals. Appl. Phys. Lett. 64, 1324–1326 (1994).

    Article  ADS  Google Scholar 

  12. Kaindl, R., Eickemeyer, F., Woerner, M. & Elsaesser, T. Broadband phase-matched difference frequency mixing of femtosecond pulses in GaSe: experiment and theory. Appl. Phys. Lett. 75, 1060–1062 (1999).

    Article  ADS  Google Scholar 

  13. Huber, R., Brodschelm, A., Tauser, F. & Leitenstorfer, A. Generation and field-resolved detection of femtosecond electromagnetic pulses tunable up to 41 THz. Appl. Phys. Lett. 76, 3191–3193 (2000).

    Article  ADS  Google Scholar 

  14. Zheng, X., Sinyukov, A. & Hayden, L. M. Broadband and gap-free response of a terahertz system based on a poled polymer emitter–sensor pair. Appl. Phys. Lett. 87, 081115 (2005).

    Article  ADS  Google Scholar 

  15. Zheng, X., McLaughlin, C. V., Cunningham, P. & Hayden, L. M. Organic broadband terahertz sources and sensors. J. Nanoelectron. Optoelectron. 2, 58–76 (2007).

    Article  Google Scholar 

  16. Brunner, F. et al. A hydrogen-bonded organic nonlinear optical crystal for high-efficiency terahertz generation and detection. Opt. Express 16, 16496–16508 (2008).

    Article  ADS  Google Scholar 

  17. Katayama, I. et al. Ultrabroadband terahertz generation using 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium tosylate single crystals. Appl. Phys. Lett. 97, 021105 (2010).

    Article  ADS  Google Scholar 

  18. Shan, J. & Heinz, T. F. in Ultrafast Dynamical Processes in Semiconductors (ed. Tsen, K.-T.) 1–56 (Springer, 2004).

    Book  Google Scholar 

  19. Apostolopoulos, V. & Barnes, M. THz emitters based on the photo-Dember effect. J. Phys. D 47, 374002 (2014).

    Article  Google Scholar 

  20. Klatt, G. et al. Terahertz emission from lateral photo-Dember currents. Opt. Express 18, 4939–4947 (2010).

    Article  ADS  Google Scholar 

  21. Shen, Y., Upadhya, P., Linfield, E., Beere, H. & Davies, A. Ultrabroadband terahertz radiation from low-temperature-grown GaAs photoconductive emitters. Appl. Phys. Lett. 83, 3117–3119 (2003).

    Article  ADS  Google Scholar 

  22. Winnerl, S. Scalable microstructured photoconductive terahertz emitters. J. Infrared Millim. Terahertz Waves 33, 431–454 (2012).

    Article  Google Scholar 

  23. Hale, P. et al. 20 THz broadband generation using semi-insulating GaAs interdigitated photoconductive antennas. Opt. Express 22, 26358–26364 (2014).

    Article  ADS  Google Scholar 

  24. Berry, C., Wang, N., Hashemi, M., Unlu, M. & Jarrahi, M. Significant performance enhancement in photoconductive terahertz optoelectronics by incorporating plasmonic contact electrodes. Nature Commun. 4, 1622 (2013).

    Article  ADS  Google Scholar 

  25. Thomson, M. D., Kreß, M., Löffler, T. & Roskos, H. G. Broadband THz emission from gas plasmas induced by femtosecond optical pulses: from fundamentals to applications. Laser Photon. Rev. 1, 349–368 (2007).

    Article  ADS  Google Scholar 

  26. Kim, K., Glownia, J., Taylor, A. J. & Rodriguez, G. High-power broadband terahertz generation via two-color photoionization in gases. IEEE J. Quantum Electron. 48, 797–805 (2012).

    Article  ADS  Google Scholar 

  27. Lu, X. & Zhang, X. C. Investigation of ultra-broadband terahertz time-domain spectroscopy with terahertz wave gas photonics. Front. Optoelectron. 7, 121–155 (2013).

    Article  Google Scholar 

  28. Bartel, T., Gaal, P., Reimann, K., Woerner, M. & Elsaesser, T. Generation of single-cycle THz transients with high electric-field amplitudes. Opt. Lett. 30, 2805–2807 (2005).

    Article  ADS  Google Scholar 

  29. Buccheri, F. & Zhang, X. C. Terahertz emission from laser-induced microplasma in ambient air. Optica 2, 366–369 (2015).

    Article  ADS  Google Scholar 

  30. Ramanandan, G., Ramakrishnan, G., Kumar, N., Adam, A. & Planken, P. Emission of terahertz pulses from nanostructured metal surfaces. J. Phys. D 47, 374003 (2014).

    Article  Google Scholar 

  31. Zhang, L. et al. High-power THz to IR emission by femtosecond laser irradiation of random 2D metallic nanostructures. Sci. Rep. 5, 12536 (2015).

    Article  ADS  Google Scholar 

  32. Zhukov, V., Chulkov, E. & Echenique, P. Lifetimes and inelastic mean free path of low-energy excited electrons in Fe, Ni, Pt, and Au: ab initio GW + T calculations. Phys. Rev. B 73, 125105 (2006).

    Article  ADS  Google Scholar 

  33. Laman, N. & Grischkowsky, D. Terahertz conductivity of thin metal films. Appl. Phys. Lett. 93, 051105 (2008).

    Article  ADS  Google Scholar 

  34. Ramakrishnan, G. & Planken, P. Percolation-enhanced generation of terahertz pulses by optical rectification on ultrathin gold films. Opt. Lett. 36, 2572–2574 (2011).

    Article  ADS  Google Scholar 

  35. Polyushkin, D., Hendry, E., Stone, E. & Barnes, W. THz generation from plasmonic nanoparticle arrays. Nano Lett. 11, 4718–4724 (2011).

    Article  ADS  Google Scholar 

  36. Kadlec, F., Kuzel, P. & Coutaz, J. Study of terahertz radiation generated by optical rectification on thin gold films. Opt. Lett. 30, 1402–1404 (2005).

    Article  ADS  Google Scholar 

  37. Welsh, G. H., Hunt, N. T. & Wynne, K. Terahertz-pulse emission through laser excitation of surface plasmons in a metal grating. Phys. Rev. Lett. 98, 026803 (2007).

    Article  ADS  Google Scholar 

  38. Saitoh, E., Ueda, M., Miyajima, H. & Tatara, G. Conversion of spin current into charge current at room temperature: inverse spin-Hall effect. Appl. Phys. Lett. 88, 182509 (2006).

    Article  ADS  Google Scholar 

  39. Hoffmann, A. Spin Hall effects in metals. IEEE Trans. Magn. 49, 5172–5193 (2013).

    Article  ADS  Google Scholar 

  40. Sinova, J. et al. Spin Hall effects. Rev. Mod. Phys. 87, 1213–1260 (2015).

    Article  ADS  Google Scholar 

  41. Wei, D. et al. Spin Hall voltages from a.c. and d.c. spin currents. Nature Commun. 5, 3768 (2014).

    Article  ADS  Google Scholar 

  42. Battiato, M., Carva, K. & Oppeneer, P. M. Superdiffusive spin transport as a mechanism of ultrafast demagnetization. Phys. Rev. Lett. 105, 027203 (2010).

    Article  ADS  Google Scholar 

  43. Melnikov, A. et al. Ultrafast transport of laser-excited spin polarized carriers in Au/Fe/MgO(001). Phys. Rev. Lett. 107, 076601 (2011).

    Article  ADS  Google Scholar 

  44. Kampfrath, T. et al. Terahertz spin current pulses controlled by magnetic heterostructures. Nature Nanotech. 8, 256–260 (2013).

    Article  ADS  Google Scholar 

  45. Héroux, J. B., Ino, Y., Kuwata-Gonokami, M., Hashimoto, Y. & Katsumoto, S. Terahertz radiation emission from GaMnAs. Appl. Phys. Lett. 88, 221110 (2006).

    Article  ADS  Google Scholar 

  46. Jin, Z. et al. Accessing the fundamentals of magnetotransport in metals with terahertz probes. Nature Phys. 11, 761–766 (2015).

    Article  ADS  Google Scholar 

  47. Leitenstorfer, A., Hunsche, S., Shah, J., Nuss, M. & Knox, W. Detectors and sources for ultrabroadband electro-optic sampling: experiment and theory. Appl. Phys. Lett. 74, 1516–1518 (1999).

    Article  ADS  Google Scholar 

  48. Kontani, H., Tanaka, T., Hirashima, D., Yamada, K. & Inoue, J. Giant orbital Hall effect in transition metals: origin of large spin and anomalous Hall effects. Phys. Rev. Lett. 102, 016601 (2009).

    Article  ADS  Google Scholar 

  49. D'Angelo, F., Mics, Z., Bonn, M. & Turchinovich, D. Ultra-broadband THz time-domain spectroscopy of common polymers using THz air photonics. Opt. Express 22, 12475–12485 (2014).

    Article  ADS  Google Scholar 

  50. Blanchard, F. et al. Generation of 1.5 μJ single-cycle terahertz pulses by optical rectification from a large aperture ZnTe crystal. Opt. Express 15, 13212–13220 (2007).

    Article  ADS  Google Scholar 

  51. Liu, M. et al. Terahertz-field-induced insulator-to-metal transition in vanadium dioxide metamaterial. Nature 487, 345–348 (2012).

    Article  ADS  Google Scholar 

  52. Vicario, C. et al. Off-resonant magnetization dynamics phase-locked to an intense phase-stable terahertz transient. Nature Photon. 7, 720–723 (2013).

    Article  ADS  Google Scholar 

  53. Boulle, O., Malinowski, G. & Kläui, M. Current-induced domain wall motion in nanoscale ferromagnetic elements. Mater. Sci. Eng. R 72, 159–187 (2011).

    Article  Google Scholar 

  54. Yeh, P. Optical Waves in Layered Media (Wiley, 2005).

    Google Scholar 

  55. Liang, X., Xu, X., Zheng, R., Lum, Z. & Qiu, J. Optical constant of CoFeB thin film measured with the interference enhancement method. Appl. Opt. 54, 1557–1563 (2015).

    Article  ADS  Google Scholar 

  56. Ordal, M., Bell, R., Alexander, R. Jr, Newquist, L. & Querry, M. Optical properties of Al, Fe, Ti, Ta, W, and Mo at submillimeter wavelengths. Appl. Opt. 27, 1203–1209 (1988).

    Article  ADS  Google Scholar 

  57. Nuss, M. C. & Orenstein, J. in Millimeter and Submillimeter Wave Spectroscopy of Solids (ed. Gruener, G.) Ch. 2 (Springer, 1998).

    Google Scholar 

  58. Kampfrath, T., Nötzold, J. & Wolf, M. Sampling of broadband terahertz pulses with thick electrooptic crystals. Appl. Phys. Lett. 90, 231113 (2007).

    Article  ADS  Google Scholar 

  59. Gallot, G. & Grischkowsky, D. Electro-optic detection of terahertz radiation. J. Opt. Soc. Am. B 16, 1204–1212 (1999).

    Article  ADS  Google Scholar 

  60. Dietze, D., Unterrainer, K. & Darmo, J. Dynamically phase-matched terahertz generation. Opt. Lett. 37, 1047–1049 (2012).

    Article  ADS  Google Scholar 

  61. Zheng, X., McLaughlin, C., Leahy-Hoppa, M., Sinyukov, A. & Hayden, L. Modeling a broadband terahertz system based on an electro-optic polymer emitter–sensor pair. J. Opt. Soc. Am. B 23, 1338–1347 (2006).

    Article  ADS  Google Scholar 

  62. Mills, D. L. Nonlinear Optics: Basic Concepts (Springer, 1991).

    Book  Google Scholar 

  63. Mosendz, O. et al. Quantifying spin Hall angles from spin pumping: experiments and theory. Phys. Rev. Lett. 104, 046601 (2010).

    Article  ADS  Google Scholar 

  64. Freimuth, F., Blügel, S. & Mokrousov, Y. Anisotropic spin Hall effect from first principles. Phys. Rev. Lett. 105, 246602 (2010).

    Article  ADS  Google Scholar 

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Acknowledgements

The authors thank S. Winnerl for providing a TeraSED3 emitter and for stimulating discussions. The authors acknowledge the German Science Foundation for funding through SPP 1538/SpinCaT (Berlin, Greifswald, Jülich and Mainz groups) and through SFB TRR 173/Spin+X (Mainz group). The European Union is acknowledged for funding through ERC H2020 CoG project TERAMAG/grant no. 681917 (T.K.), FP7 project CRONOS/grant no. 280879 (T.K. and M.W.), FP7 Marie Curie ITN WALL project/grant no. 608031 (J.S., G.J. and M.K.), Career Integration Grant LIGHTER/grant no. 334324 (D.T.) and FP7 project FemtoSpin/grant no. 281043 (P.M. and P.M.O.). The authors are grateful for support from the Max Planck Society (T.K. and D.T.), the Swedish Research Council, the Röntgen-Ångström Cluster, and the K. and A. Wallenberg Foundation (P.M. and P.M.O.), the Samsung SGMI programme, the EFRE Program of the state of Rhineland Palatinate, TT-DINEMA, the Excellence Graduate School MAINZ (GSC 266) and the state research centre CINEMA (Mainz group). F.F. and Y.M. acknowledge Jülich Supercomputing Centre for computing time.

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Authors and Affiliations

  1. Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Berlin, 14195, Germany

    T. Seifert, L. Braun, M. Wolf & T. Kampfrath

  2. Institute of Physics, Johannes Gutenberg University, Mainz, 55128, Germany

    S. Jaiswal, A. Kronenberg, J. Henrizi, M. Jourdan, G. Jakob & M. Kläui

  3. Singulus Technologies AG, Kahl am Main, 63796, Germany

    S. Jaiswal

  4. Institute of Physics, Ernst Moritz Arndt University, Greifswald, 17489, Germany

    U. Martens & M. Münzenberg

  5. Department of Physics, University of Maryland Baltimore County, Baltimore, 21250, Maryland, USA

    J. Hannegan & L. M. Hayden

  6. Department of Physics and Astronomy, Uppsala University, SE-75120 Uppsala, Sweden

    P. Maldonado & P. M. Oppeneer

  7. Peter Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

    F. Freimuth & Y. Mokrousov

  8. Institute for Optics and Atomic Physics, Technical University Berlin and Helmholtz-Zentrum Berlin fϋr Materialien und Energie, 12489 Berlin, Germany

    I. Radu

  9. Institut de Physique et Chimie des Matériaux de Strasbourg, 67200 Strasbourg, France

    E. Beaurepaire

  10. Max Planck Institute for Polymer Research, Mainz, 55128, Germany

    D. Turchinovich

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  1. T. Seifert
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Contributions

T.K. and T.S. conceived the experiments. T.K. and I.R. carried out preliminary measurements. S.J., U.M., A.K., J.He., E.B., M.J., G.J., M.M. and M.K. fabricated the spintronic emitters and optimized the fabrication process. L.B., T.S. and T.K. built the terahertz emission set-up. J.Ha. and L.M.H. fabricated the LAPC electrooptic detectors. T.S. performed the terahertz experiments and optical sample characterization. T.S. and T.K. analysed experimental data with contributions from D.T. and M.K. T.K. and T.S. developed the analytical terahertz-emitter model with contributions from F.F. and Y.M. F.F. and Y.M. calculated spin-Hall conductivities. P.M. and P.M.O. conducted calculations of the ultrafast spin transport. T.K., T.S., D.T., M.W. and M.K. co-wrote the paper. All authors contributed to discussing the results and writing the paper.

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Correspondence to T. Kampfrath.

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Seifert, T., Jaiswal, S., Martens, U. et al. Efficient metallic spintronic emitters of ultrabroadband terahertz radiation. Nature Photon 10, 483–488 (2016). https://doi.org/10.1038/nphoton.2016.91

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