OSA's Digital Library

Optics Express

Optics Express

  • Editor: Michael Duncan
  • Vol. 14, Iss. 21 — Oct. 16, 2006
  • pp: 9988–9999

Plasmons in nearly touching metallic nanoparticles: singular response in the limit of touching dimers

Isabel Romero, Javier Aizpurua, Garnett W. Bryant, and F. Javier García de Abajo  »View Author Affiliations

Optics Express, Vol. 14, Issue 21, pp. 9988-9999 (2006)

View Full Text Article

Enhanced HTML    Acrobat PDF (721 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools



The response of gold nanoparticle dimers is studied theoretically near and beyond the limit where the particles are touching. As the particles approach each other, a dominant dipole feature is observed that is pushed into the infrared due to interparticle coupling and that is associated with a large pileup of induced charge in the interparticle gap. The redshift becomes singular as the particle separation decreases. The response weakens for very small separation when the coupling across the interparticle gap becomes so strong that dipolar oscillations across the pair are inhibited. Lower-wavelength, higher-order modes show a similar separation dependence in nearly touching dimers. After touching, singular behavior is observed through the emergence of a new infrared absorption peak, also accompanied by huge charge pileup at the interparticle junction, if initial interparticle contact is made at a single point. This new mode is distinctly different from the lowest mode of the separated dimer. When the junction is made by contact between flat surfaces, charge at the junction is neutralized and mode evolution is continuous through contact. The calculated singular response explains recent experiments on metallic nanoparticle dimers and is relevant in the design of nanoparticle-based sensors and plasmon circuits.

© 2006 Optical Society of America

OCIS Codes
(240.6680) Optics at surfaces : Surface plasmons
(350.4990) Other areas of optics : Particles

ToC Category:
Optics at Surfaces

Original Manuscript: July 27, 2006
Revised Manuscript: August 29, 2006
Manuscript Accepted: August 29, 2006
Published: October 16, 2006

Isabel Romero, Javier Aizpurua, Garnett W. Bryant, and F. Javier García De Abajo, "Plasmons in nearly touching metallic nanoparticles: singular response in the limit of touching dimers," Opt. Express 14, 9988-9999 (2006)

Sort:  Author  |  Year  |  Journal  |  Reset  


  1. M. Faraday, "Experimental relations of gold (and other metals) to light," Philos. Trans. R. Soc. London 147, 145-181 (1857). [CrossRef]
  2. U. Kreibig and M. Vollmer, Optical Properties of Metal Clusters (Springer-Verlag, Berlin, 1996).
  3. S. Schultz, D. R. Smith, J. J. Mock, and D. A. Schultz, "Single-target molecule detection with nonbleaching multicolor optical immunolabels," Proc. Natl. Acad. Sci. 97, 996-1001 (2000). [CrossRef] [PubMed]
  4. E. Prodan, C. Radloff, N. J. Halas, and P. Nordlander, "A hybridization model for the plasmon response of complex nanostructures," Science,  302, 419-422 (2003). [CrossRef] [PubMed]
  5. J. Aizpurua, P. Hanarp, D. S. Sutherland, M. Käll, G. W. Bryant, and F. J. García de Abajo, "Optical properties of gold nanorings," Phys. Rev. Lett. 90, 057401 (2003). [CrossRef] [PubMed]
  6. K. G. Thomas, S. Barazzouk, B. I. Ipe, S. T. S. Joseph, and P. V. Kamat, "Uniaxial plasmon coupling through longitudinal self-assembly of gold nanorods," J. Phys. Chem. B,  108, 13066-13068 (2004). [CrossRef]
  7. M. El-Kouedi and C. A. Foss, "Optical properties of gold-silver iodide nanoparticle pair structures," J. Phys. Chem. B 104, 4031-4037 (2000). [CrossRef]
  8. T. Ung, L. M. Liz-Marzán, and P. Mulvaney, "Optical properties of thin films of Au@SiO2 particles," J. Phys. Chem. B 105, 3441-3452 (2001). [CrossRef]
  9. H. Tamaru, H. Kuwata, H. T. Miyazaki, and K. Miyano, "Resonant light scattering from individual Ag nanoparticles and particle pairs," Appl. Phys. Lett. 80, 1826-1828 (2002). [CrossRef]
  10. W. Rechberger, A. Hohenau, A. Leitner, J. R. Krenn, B. Lamprecht, and F. R. Aussenegg, "Optical properties of two interacting gold nanoparticles," Opt. Commun. 220, 137-141 (2003). [CrossRef]
  11. T. Atay, J. H. Song, and A. V. Nurmikko, "Strongly interacting plasmon nanoparticle pairs: from dipole-dipole interaction to conductively coupled regime," Nano Lett. 4, 1627-1631 (2004). [CrossRef]
  12. L. Gunnarsson, T. Rindzevicius, J. Prikulis, B. Kasemo, M. Käll, S. Zou, and G. C. Schatz, "Confined plasmons in nanofabricated single silver particle pairs: experimental observations of strong interparticle interactions," J. Phys. Chem. B 109, 1079-1087 (2005). [CrossRef]
  13. C. E. Talley, J. B. Jackson, C. Oubre, N. K. Grady, C. W. Hollars, S. M. Lane, T. R. Huser, P. Nordlander, and N. J. Halas, "Surface-enhanced Raman scattering from individual Au nanoparticles and nanoparticle dimer substrates," Nano Lett. 5, 1569-1574 (2005). [CrossRef] [PubMed]
  14. R. Rupin, "Surface modes of two spheres," Phys. Rev. B 26, 3440-3444 (1982). [CrossRef]
  15. M. Schmeits and L. Dambly, "Fast-electron scattering by bispherical surface-plasmon modes," Phys. Rev. B 44, 12706-12712 (1991). [CrossRef]
  16. A. V. Vagov, A. Radchik, and G. B. Smith, "Optical response of arrays of spheres from the theory of hypercomplex variables," Phys. Rev. Lett. 73, 1035-1038 (1994). [CrossRef] [PubMed]
  17. A. V. Radchik, A. V. Paley, G. B. Smith, and A. V. Vagov, "Polarization and resonant absorption in intersecting cylinders and spheres," J. Appl. Phys. 76, 4827-4835 (1994). [CrossRef]
  18. G. B. Smith, W. E. Vargas, G. A. Niklasson, J. A. Sotelo, A. V. Paley, and A. V. Radchik, "Optical properties of a pair of spheres: comparison of different theories," Opt. Commun. 15, 8-12 (1995). [CrossRef]
  19. J. Aizpurua, A. Rivacoba, N. Zabala, and F. J. García de Abajo, "Collective excitations in an infinite set of aligned spheres," Surf. Sci. 402-404, 418-423 (1998). [CrossRef]
  20. F. J. García de Abajo and A. Howie, "Relativistic electron energy loss and electron-induced photon emission in inhomogeneous dielectrics," Phys. Rev. Lett., 80, 5180-5183 (1998); "Retarded field calculation of electron energy loss in inhomogeneous dielectrics," Phys. Rev. B 75, 115418 (2002). [CrossRef]
  21. F. J. García de Abajo, "Interaction of raidation and fast electrons with clusters of dielectrics: a multiple scattering approach," Phys. Rev. Lett. 82, 2776-2779 (1999). [CrossRef]
  22. A. Pack, M. Hietschold, and R. Wannemacher, "Failure of local mie theory: optical spectra of colloidal aggregates," Opt. Commun. 194, 277-287 (2001). [CrossRef]
  23. H. Xu and M. Käll, "Surface-plasmon-enhanced optical forces in silver nanoaggregates," Phys.Rev. Lett. 89, 246802 (2002). [CrossRef] [PubMed]
  24. A. A. Lalayan, K. S. Bagdasaryan, P. G. Petrosyan, Kh. V. Nerkararyan, and J. B. Ketterson, "Anomalous field enhancement from the superfocusing of surface plasmons at contacting silver surfaces," J. Appl. Phys. 91, 2965-2968 (2002). [CrossRef]
  25. P. Nordlander, C. Oubre, E. Prodan, K. Li, and M. I. Stockman, "Plasmon hybridization in nanoparticle dimers," Nano Lett. 4, 899-903 (2004). [CrossRef]
  26. J. J. Xiao, J. P. Huang, and K. W. Yu, "Optical response of strongly coupled metal nanoparticles in dimer arrays," Phys. Rev. B 71, 045404 (2005). [CrossRef]
  27. J. Aizpurua, G. W. Bryant, L. J. Richter, F. J. García de Abajo, B. K. Kelly, and T. Mallouk, "Optical properties of coupled metallic nanorods for field-enhanced spectroscopy," Phys. Rev. B 71, 235420 (2005). [CrossRef]
  28. P. Nordlander and E. Prodan, "Plasmon hybridization in nanoparticles near metallic surfaces," Nano Lett. 4, 2209-2213 (2004). [CrossRef]
  29. D. A. Genov, A. K. Sarychev, V. M. Shalaev, and A. Wei, "Resonant field enhancements from metal nanoparticle arrays," Nano Lett. 4, 153-158 (2004). [CrossRef]
  30. E. D. Palik, Handbook of Optical Constants of Solids (Academic Press, New York, 1985).
  31. F. Claro, "Absorption spectrum of neighboring dielectric grains," Phys. Rev. B 25, 7875-7876 (1982). [CrossRef]
  32. F. Claro, "Multipolar effects in particulate matter," Solid State Commun. 49, 229-232 (1984). [CrossRef]
  33. A. O. Govorov, S. A. Studenikin, and W. R. Frank, "Low-frequency plasmons in coupled electronic microstructures," Phys. Solid State 40, 499-502 (1998). [CrossRef]
  34. F. J. García de Abajo and J. Aizpurua, "Numerical simulation of electron energy loss near inhomogeneous dielectrics," Phys. Rev. B 56, 15873-15884 (1997). [CrossRef]
  35. L. C. Davis, "Electrostatic edge modes of a dielectric wedge," Phys. Rev. B 14, 5523-5525 (1976). [CrossRef]
  36. D. R. McKenzie and R. C. McPhedran, "Exact modelling of cubic lattice permittivity and conductivity," Nature 265, 128-129 (1977). [CrossRef]
  37. C. Pecharromán and J. S. Moya, "Experimental evidence of a giant capacitance in insulator-conductor composites at the percolation threshold," Adv. Mater. 12, 294-297 (2000). [CrossRef]
  38. C. Pecharromán, F. Esteban-Betegón, J. F. Bartolomé, S. López-Esteban, and J. S. Moya, "New percolative BaTiO3-Ni composites with a high and frequency-independent dielectric constant (εr≈80 000)," Adv. Mater. 13, 1541-1544 (2001). [CrossRef]
  39. C. C. Chen and Y. C. Chou, "Electrical-conductivity fluctuations near the percolation threshold," Phys. Rev. Lett. 54, 2529-2532 (1985). [CrossRef] [PubMed]
  40. R. Fuchs and F. Claro, "Multipolar response of small metallic spheres: nonlocal theory," Phys. Rev. B 35, 3722-3727 (1987). [CrossRef]
  41. S. A. Maier, P. G. Kik, H. A. Atwater, S. Meltzer, E. Harel, B. E. Koel, and A. A. G. Requicha, "Local detection of electromagnetic energy transport below the diffraction limit in metal nanoparticle plasmon waveguides," Nat. Mater. 2, 229-232 (2003). [CrossRef]
  42. L. A. Sweatlock, S. A. Maier, H. A. Atwater, J. J. Penninkhof, and A. Polman, "Highly confined electromagnetic fields in arrays of strongly coupled Ag nanoparticles," Phys. Rev. B 71, 235408 (2005). [CrossRef]
  43. J. A. Dionne, L. A. Sweatlock, H. A. Atwater, and A. Polman, "Plasmon slot waveguides: towards chip-scale propagation with subwavelength-scale localization," Phys. Rev. B 73, 035407 (2006). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited