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Vectorial near-field coupling


The coherent exchange of optical near fields between two neighbouring dipoles plays an essential role in the optical properties, quantum dynamics and thus the function of many naturally occurring and artificial nanosystems. These interactions are challenging to quantify experimentally. They extend over only a few nanometres and depend sensitively on the detuning, dephasing and relative orientation (that is, the vectorial properties) of the coupled dipoles. Here, we introduce plasmonic nanofocusing spectroscopy to record coherent light scattering spectra with 5 nm spatial resolution from the apex of a conical gold nanotaper. The apex is excited solely by evanescent fields and coupled to plasmon resonances in a single gold nanorod. We resolve resonance energy shifts and line broadenings as a function of dipole distance and relative orientation. We demonstrate how these phenomena arise from mode couplings between different vectorial components of the interacting optical near fields, specifically from the coupling of the nanorod to both transverse and longitudinal polarizabilities of the taper apex.

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Fig. 1: Plasmonic nanofocusing scattering spectroscopy of individual gold nanorods.
Fig. 2: High-spatial-resolution plasmonic nanofocusing spectra of a single gold nanorod.
Fig. 3: Distance-dependent plasmonic nanofocusing spectra of an individual gold nanorod.
Fig. 4: Fano line analysis of high-spatial-resolution plasmonic nanofocusing spectra recorded on a single gold nanorod.
Fig. 5: Coupled dipole simulations of plasmonic nanofocusing spectra of a single gold nanorod.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.


  1. 1.

    Ostroumov, E. E., Mulvaney, R. M., Cogdell, R. J. & Scholes, G. D. Broadband 2D electronic spectroscopy reveals a carotenoid dark state in purple bacteria. Science 340, 52–56 (2013).

    CAS  Article  Google Scholar 

  2. 2.

    Scholes, G. D., Fleming, G. R., Olaya-Castro, A. & van Grondelle, R. Lessons from nature about solar light harvesting. Nat. Chem. 3, 763–774 (2011).

    CAS  Article  Google Scholar 

  3. 3.

    Hildner, R., Brinks, D., Nieder, J. B., Cogdell, R. J. & van Hulst, N. F. Quantum coherent energy transfer over varying pathways in single light-harvesting complexes. Science 340, 1448–1451 (2013).

    CAS  Article  Google Scholar 

  4. 4.

    Unold, T., Mueller, K., Lienau, C., Elsaesser, T. & Wieck, A. D. Optical control of excitons in a pair of quantum dots coupled by the dipole–dipole interaction. Phys. Rev. Lett. 94, 137404 (2005).

    Article  Google Scholar 

  5. 5.

    Krenner, H. J. et al. Direct observation of controlled coupling in an individual quantum dot molecule. Phys. Rev. Lett. 94, 057402 (2005).

    CAS  Article  Google Scholar 

  6. 6.

    Biolatti, E., Iotti, R. C., Zanardi, P. & Rossi, F. Quantum information processing with semiconductor macroatoms. Phys. Rev. Lett. 85, 5647–5650 (2000).

    CAS  Article  Google Scholar 

  7. 7.

    Zhang, Y. et al. Visualizing coherent intermolecular dipole–dipole coupling in real space. Nature 531, 623–627 (2016).

    Article  Google Scholar 

  8. 8.

    Hettich, C. et al. Nanometer resolution and coherent optical dipole coupling of two individual molecules. Science 298, 385–389 (2002).

    CAS  Article  Google Scholar 

  9. 9.

    Kern, J. et al. Atomic-scale confinement of resonant optical fields. Nano Lett. 12, 5504–5509 (2012).

    CAS  Article  Google Scholar 

  10. 10.

    Deutsch, B., Hillenbrand, R. & Novotny, L. Visualizing the optical interaction tensor of a gold nanoparticle pair. Nano Lett. 10, 652–656 (2010).

    CAS  Article  Google Scholar 

  11. 11.

    Lovera, A., Gallinet, B., Nordlander, P. & Martin, O. J. F. Mechanisms of Fano resonances in coupled plasmonic systems. ACS Nano 7, 4527–4536 (2013).

    CAS  Article  Google Scholar 

  12. 12.

    Mühlschlegel, P., Eisler, H. J., Martin, O. J. F., Hecht, B. & Pohl, D. W. Resonant optical antennas. Science 308, 1607–1609 (2005).

    Article  Google Scholar 

  13. 13.

    Carminati, R., Greffet, J. J., Henkel, C. & Vigoureux, J. M. Radiative and non-radiative decay of a single molecule close to a metallic nanoparticle. Opt. Commun. 261, 368–375 (2006).

    CAS  Article  Google Scholar 

  14. 14.

    Chikkaraddy, R. et al. Single-molecule strong coupling at room temperature in plasmonic nanocavities. Nature 535, 127–130 (2016).

    CAS  Article  Google Scholar 

  15. 15.

    Dulkeith, E. et al. Fluorescence quenching of dye molecules near gold nanoparticles: radiative and nonradiative effects. Phys. Rev. Lett. 89, 203002 (2002).

    CAS  Article  Google Scholar 

  16. 16.

    Ha, T. et al. Probing the interaction between two single molecules: fluorescence resonance energy transfer between a single donor and a single acceptor. Proc. Natl Acad. Sci. USA 93, 6264–6268 (1996).

    CAS  Article  Google Scholar 

  17. 17.

    Haedler, A. T. et al. Long-range energy transport in single supramolecular nanofibres at room temperature. Nature 523, 196–U127 (2015).

    CAS  Article  Google Scholar 

  18. 18.

    Gaebel, T. et al. Room-temperature coherent coupling of single spins in diamond. Nat. Phys. 2, 408–413 (2006).

    CAS  Article  Google Scholar 

  19. 19.

    Dolde, F. et al. Room-temperature entanglement between single defect spins in diamond. Nat. Phys. 9, 139–143 (2013).

    CAS  Article  Google Scholar 

  20. 20.

    Steidtner, J. & Pettinger, B. Tip-enhanced Raman spectroscopy and microscopy on single dye molecules with 15 nm resolution. Phys. Rev. Lett. 100, 236101 (2008).

    Article  Google Scholar 

  21. 21.

    Zhang, R. et al. Chemical mapping of a single molecule by plasmon-enhanced Raman scattering. Nature 498, 82–86 (2013).

    CAS  Article  Google Scholar 

  22. 22.

    Dorfmüller, J. et al. Plasmonic nanowire antennas: experiment, simulation and theory. Nano Lett. 10, 3596–3603 (2010).

    Article  Google Scholar 

  23. 23.

    Savage, K. J. et al. Revealing the quantum regime in tunnelling plasmonics. Nature 491, 574–577 (2012).

    CAS  Article  Google Scholar 

  24. 24.

    Stockman, M. I. Nanofocusing of optical energy in tapered plasmonic waveguides. Phys. Rev. Lett. 93, 137404 (2004).

    Article  Google Scholar 

  25. 25.

    Ropers, C. et al. Grating-coupling of surface plasmons onto metallic tips: a nanoconfined light source. Nano Lett. 7, 2784–2788 (2007).

    CAS  Article  Google Scholar 

  26. 26.

    Neacsu, C. C. et al. Near-field localization in plasmonic superfocusing: a nanoemitter on a tip. Nano Lett. 10, 592–596 (2010).

    CAS  Article  Google Scholar 

  27. 27.

    Gramotnev, D. K. & Bozhevolnyi, S. I. Nanofocusing of electromagnetic radiation. Nat. Photon. 8, 14–23 (2014).

    Article  Google Scholar 

  28. 28.

    Schmidt, S. et al. Adiabatic nanofocusing on ultrasmooth single-crystalline gold tapers creates a 10-nm-sized light source with few-cycle time resolution. ACS Nano 6, 6040–6048 (2012).

    CAS  Article  Google Scholar 

  29. 29.

    Kravtsov, V., Ulbricht, R., Atkin, J. & Raschke, M. B. Plasmonic nanofocused four-wave mixing for femtosecond near-field imaging. Nat. Nanotechnol. 11, 459–464 (2016).

    CAS  Article  Google Scholar 

  30. 30.

    Vogelsang, J. et al. Ultrafast electron emission from a sharp metal nanotaper driven by adiabatic nanofocusing of surface plasmons. Nano Lett. 15, 4685–4691 (2015).

    CAS  Article  Google Scholar 

  31. 31.

    Babadjanyan, A. J., Margaryan, N. L. & Nerkararyan, K. V. Superfocusing of surface polaritons in the conical structure. J. Appl. Phys. 87, 3785–3788 (2000).

    CAS  Article  Google Scholar 

  32. 32.

    Becker, S. F. et al. Gap-plasmon-enhanced nanofocusing near-field microscopy. ACS Photonics 3, 223–232 (2016).

    CAS  Article  Google Scholar 

  33. 33.

    Genet, C., van Exter, M. P. & Woerdman, J. P. Fano-type interpretation of red shifts and red tails in hole array transmission spectra. Opt. Commun. 225, 331–336 (2003).

    CAS  Article  Google Scholar 

  34. 34.

    Ropers, C. et al. Femtosecond light transmission and subradiant damping in plasmonic crystals. Phys. Rev. Lett. 94, 113901 (2005).

    CAS  Article  Google Scholar 

  35. 35.

    Kollmann, H. et al. Fourier-transform spatial modulation spectroscopy of single gold nanorods. Nanophotonics 7, 715–726 (2018).

    CAS  Article  Google Scholar 

  36. 36.

    Purcell, E. M. Spontaneous emission probabilities at radio frequencies. Phys. Rev. 69, 681–681 (1946).

    Article  Google Scholar 

  37. 37.

    Gerard, J. M. et al. Enhanced spontaneous emission by quantum boxes in a monolithic optical microcavity. Phys. Rev. Lett. 81, 1110–1113 (1998).

    CAS  Article  Google Scholar 

  38. 38.

    Talebi, N. et al. Excitation of mesoscopic plasmonic tapers by relativistic electrons: phase matching versus eigenmode resonances. ACS Nano 9, 7641–7648 (2015).

    CAS  Article  Google Scholar 

  39. 39.

    Bouhelier, A., Beversluis, M., Hartschuh, A. & Novotny, L. Near-field second-harmonic generation induced by local field enhancement. Phys. Rev. Lett. 90, 013903 (2003).

    CAS  Article  Google Scholar 

  40. 40.

    Sönnichsen, C. et al. Drastic reduction of plasmon damping in gold nanorods. Phys. Rev. Lett. 88, 077402 (2002).

    Article  Google Scholar 

  41. 41.

    Novotny, L. Effective wavelength scaling for optical antennas. Phys. Rev. Lett. 98, 266802 (2007).

    Article  Google Scholar 

  42. 42.

    Esmann, M. et al. k-space imaging of the eigenmodes of sharp gold tapers for scanning near-field optical microscopy. Beilstein J. Nanotech. 4, 603–610 (2013).

    Article  Google Scholar 

  43. 43.

    Neuman, T. et al. Mapping the near fields of plasmonic nanoantennas by scattering-type scanning near-field optical microscopy. Laser Photon. Rev. 9, 637–649 (2015).

    CAS  Article  Google Scholar 

  44. 44.

    Berweger, S., Atkin, J. M., Xu, X. G., Olmon, R. L. & Raschke, M. B. Femtosecond nanofocusing with full optical waveform control. Nano Lett. 11, 4309–4313 (2011).

    CAS  Article  Google Scholar 

  45. 45.

    Sadiq, D. et al. Adiabatic nanofocusing scattering-type optical nanoscopy of individual gold nanoparticles. Nano Lett. 11, 1609–1613 (2011).

    CAS  Article  Google Scholar 

  46. 46.

    Piglosiewicz, B. et al. Carrier-envelope phase effects on the strong-field photoemission of electrons from metallic nanostructures. Nat. Photon. 8, 37–42 (2014).

    CAS  Article  Google Scholar 

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The authors acknowledge financial support by the Deutsche Forschungsgemeinschaft (SPP1839 ‘Tailored Disorder’, grant LI 580/12 and SPP1840 ‘QUTIF’ grant LI 580/13), the Korea Foundation for International Cooperation of Science and Technology (Global Research Laboratory project, K20815000003) and the German–Israeli Foundation (GIF grant no. 1256 and 1074-49.10/2009). M.E. thanks the Studienstiftung des Deutschen Volkes (German Scholarship Foundation) for a PhD scholarship and the Deutsche Forschungsgemeinschaft (project 401390650). The authors thank V. Smirnov for performing supporting finite element method calculations and H. Kollmann for providing high-resolution SEM images of individual gold nanorods. The authors thank N. Talebi for discussions and supporting numerical calculations.

Author information




J.W. and G.W. prepared the nanorod samples. M.E. and S.F.B. built the SNOM set-up, prepared the nanofocusing SNOM tapers and conducted the SNOM experiments. M.E., S.F.B. and C.L. analysed the data. M.E., C.L. and R.V. performed the theoretical modelling. C.L. initiated the project, M.E. and C.L. co-wrote the manuscript. J.Z., A.C., A.K. and J.H.Z. performed the broadband tip characterization experiments and analysed these data together with M.E. and C.L. All authors discussed the results and commented on the manuscript.

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Correspondence to Christoph Lienau.

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Supplementary Figs. 1–15. Supplementary Table 1

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Esmann, M., Becker, S.F., Witt, J. et al. Vectorial near-field coupling. Nat. Nanotechnol. 14, 698–704 (2019).

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