Abstract

In this work we report on the observation of surface plasmon properties of periodic arrays of gold nanoring trimers fabricated by electron beam lithography. It is shown that the localized surface plasmon resonances of such gold ring trimers occur in the infrared spectral region and are strongly influenced by the nanoring geometry and their relative positions. Based on numerical simulations of the optical extinction spectra and of the electric near-field intensity maps, the resonances are assigned to surface plasmon states arising from the strong intra-trimer electromagnetic interaction. We show that the nanoring trimer configuration allows for generating infrared surface plasmon resonances associated with strongly localized electromagnetic energy, thus providing plasmonic nanoresonators well-suited for sensing and surface enhanced near-infrared Raman spectroscopy.

© 2010 OSA

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. S. A. Maier, M. L. Brongersma, P. G. Kik, S. Meltzer, A. A. G. Requicha, and H. A. Atwater, “Plasmonics - a route to nanoscale optical devices,” Adv. Mater. 13(19), 1501–1505 (2001).
    [CrossRef]
  2. A. V. Kabashin, P. Evans, S. Pastkovsky, W. Hendren, G. A. Wurtz, R. Atkinson, R. Pollard, V. A. Podolskiy, and A. V. Zayats, “Plasmonic nanorod metamaterials for biosensing,” Nat. Mater. 8(11), 867–871 (2009).
    [CrossRef] [PubMed]
  3. Y. B. Zheng, Y. W. Yang, L. Jensen, L. Fang, B. K. Juluri, A. H. Flood, P. S. Weiss, J. F. Stoddart, and T. J. Huang, “Active molecular plasmonics: controlling plasmon resonances with molecular switches,” Nano Lett. 9(2), 819–825 (2009).
    [CrossRef] [PubMed]
  4. K. Kneipp, Y. Wang, H. Kneipp, L. T. Perelman, I. Itzkan, R. R. Dasari, and M. S. Feld, “Single molecule detection using surface-enhanced Raman scattering,” Phys. Rev. Lett. 78(9), 1667–1670 (1997).
    [CrossRef]
  5. S. Lal, N. K. Grady, J. Kundu, C. S. Levin, J. B. Lassiter, and N. J. Halas, “Tailoring plasmonic substrates for surface enhanced spectroscopies,” Chem. Soc. Rev. 37(5), 898–911 (2008).
    [CrossRef] [PubMed]
  6. 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(5), 057401 (2003).
    [CrossRef] [PubMed]
  7. E. M. Larsson, J. Alegret, M. Käll, and D. S. Sutherland, “Sensing characteristics of NIR localized surface plasmon resonances in gold nanorings for application as ultrasensitive biosensors,” Nano Lett. 7(5), 1256–1263 (2007).
    [CrossRef] [PubMed]
  8. M. G. Banaee and K. B. Crozier, “Gold nanorings as substrates for surface-enhanced Raman scattering,” Opt. Lett. 35(5), 760–762 (2010).
    [CrossRef] [PubMed]
  9. A. M. Funston, C. Novo, T. J. Davis, and P. Mulvaney, “Plasmon coupling of gold nanorods at short distances and in different geometries,” Nano Lett. 9(4), 1651–1658 (2009).
    [CrossRef] [PubMed]
  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(1-3), 137–141 (2003).
    [CrossRef]
  11. P. K. Jain and M. A. El-Sayed, “Noble metal nanoparticle pairs: effect of medium for enhanced nanosensing,” Nano Lett. 8(12), 4347–4352 (2008).
    [CrossRef]
  12. B. Willingham, D. Brandl, and P. Nordlander, “Plasmon hybridization in nanorod dimmers,” Appl. Phys. B 93(1), 209–216 (2008).
    [CrossRef]
  13. P. Nordlander, C. Oubre, E. Prodan, K. Li, and M. I. Stockman, “Plasmon hybridization in nanoparticle dimmers,” Nano Lett. 4(5), 899–903 (2004).
    [CrossRef]
  14. 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(8), 1569–1574 (2005).
    [CrossRef] [PubMed]
  15. A. Kinkhabwala, Z. F. Yu, S. H. Fan, Y. Avlasevich, K. Mullen, and W. E. Moerner, “Large single-molecule fluorescence enhancements produced by a bowtie nanoantenna,” Nat. Photonics 3(11), 654–657 (2009).
    [CrossRef]
  16. Z. Zhang, A. Weber-Bargioni, S. W. Wu, S. Dhuey, S. Cabrini, and P. J. Schuck, “Manipulating nanoscale light fields with the asymmetric bowtie nano-colorsorter,” Nano Lett. 9(12), 4505–4509 (2009).
    [CrossRef] [PubMed]
  17. J. A. Fan, C. H. Wu, K. Bao, J. Bao, R. Bardhan, N. J. Halas, V. N. Manoharan, P. Nordlander, G. Shvets, and F. Capasso, “Self-assembled plasmonic nanoparticle clusters,” Science 328(5982), 1135–1138 (2010).
    [CrossRef] [PubMed]
  18. M. Hentschel, M. Saliba, R. Vogelgesang, H. Giessen, A. P. Alivisatos, and N. Liu, “Transition from isolated to collective modes in plasmonic oligomers,” Nano Lett. 10(7), 2721–2726 (2010).
    [CrossRef] [PubMed]
  19. J. B. Lassiter, H. Sobhani, J. A. Fan, J. Kundu, F. Capasso, P. Nordlander, and N. J. Halas, “Fano resonances in plasmonic nanoclusters: geometrical and chemical tunability,” Nano Lett. 10(8), 3184–3189 (2010).
    [CrossRef] [PubMed]
  20. V. K. Lin, S. L. Teo, R. Marty, A. Arbouet, Ch. Girard, E. Alarcon-Llado, S. H. Liu, M. Y. Han, S. Tripathy, and A. Mlayah, “Dual wavelength sensing based on interacting gold nanodisk trimers,” Nanotechnology 21(30), 305501 (2010).
    [CrossRef] [PubMed]
  21. F. J. García de Abajo and A. Howie, “Retarded field calculation of electron energy loss in inhomogeneous dielectrics”, Phys. Rev. Lett. 80, 5180–5183 (1998); “Retarded field calculation of electron energy loss in inhomogeneous dielectrics,” Phys. Rev. B 65, 115418 (2002).
  22. P. B. Johnson and R. W. Christy, “Optical constants of the nobel metals,” Phys. Rev. B 6(12), 4370–4379 (1972).
    [CrossRef]
  23. K. L. Wustholz, A. I. Henry, J. M. McMahon, R. G. Freeman, N. Valley, M. E. Piotti, M. J. Natan, G. C. Schatz, and R. P. Van Duyne, “Structure-activity relationships in gold nanoparticle dimers and trimers for surface-enhanced Raman spectroscopy,” J. Am. Chem. Soc. 132(31), 10903–10910 (2010).
    [CrossRef] [PubMed]
  24. B. Auguié and W. L. Barnes, “Diffractive coupling in gold nanoparticle arrays and the effect of disorder,” Opt. Lett. 34(4), 401–403 (2009).
    [CrossRef] [PubMed]
  25. C. Girard, “Near fields in nanostructures,” Rep. Prog. Phys. 68(8), 1883–1933 (2005).
    [CrossRef]
  26. I. Romero, J. Aizpurua, G. W. Bryant, and F. J. García De Abajo, “Plasmons in nearly touching metallic nanoparticles: singular response in the limit of touching dimers,” Opt. Express 14(21), 9988–9999 (2006).
    [CrossRef] [PubMed]
  27. J. Aizpurua, G. W. Bryant, L. J. Richter, F. J. García de Abajo, B. K. Kelley, and T. Mallouk, “Optical properties of coupled metallic nanorods for field-enhanced spectroscopy,” Phys. Rev. B 71(23), 235420 (2005).
    [CrossRef]
  28. J. B. Lassiter, J. Aizpurua, L. I. Hernandez, D. W. Brandl, I. Romero, S. Lal, J. H. Hafner, P. Nordlander, and N. J. Halas, “Close encounters between two nanoshells,” Nano Lett. 8(4), 1212–1218 (2008).
    [CrossRef] [PubMed]

2010

M. G. Banaee and K. B. Crozier, “Gold nanorings as substrates for surface-enhanced Raman scattering,” Opt. Lett. 35(5), 760–762 (2010).
[CrossRef] [PubMed]

J. A. Fan, C. H. Wu, K. Bao, J. Bao, R. Bardhan, N. J. Halas, V. N. Manoharan, P. Nordlander, G. Shvets, and F. Capasso, “Self-assembled plasmonic nanoparticle clusters,” Science 328(5982), 1135–1138 (2010).
[CrossRef] [PubMed]

M. Hentschel, M. Saliba, R. Vogelgesang, H. Giessen, A. P. Alivisatos, and N. Liu, “Transition from isolated to collective modes in plasmonic oligomers,” Nano Lett. 10(7), 2721–2726 (2010).
[CrossRef] [PubMed]

J. B. Lassiter, H. Sobhani, J. A. Fan, J. Kundu, F. Capasso, P. Nordlander, and N. J. Halas, “Fano resonances in plasmonic nanoclusters: geometrical and chemical tunability,” Nano Lett. 10(8), 3184–3189 (2010).
[CrossRef] [PubMed]

V. K. Lin, S. L. Teo, R. Marty, A. Arbouet, Ch. Girard, E. Alarcon-Llado, S. H. Liu, M. Y. Han, S. Tripathy, and A. Mlayah, “Dual wavelength sensing based on interacting gold nanodisk trimers,” Nanotechnology 21(30), 305501 (2010).
[CrossRef] [PubMed]

K. L. Wustholz, A. I. Henry, J. M. McMahon, R. G. Freeman, N. Valley, M. E. Piotti, M. J. Natan, G. C. Schatz, and R. P. Van Duyne, “Structure-activity relationships in gold nanoparticle dimers and trimers for surface-enhanced Raman spectroscopy,” J. Am. Chem. Soc. 132(31), 10903–10910 (2010).
[CrossRef] [PubMed]

2009

B. Auguié and W. L. Barnes, “Diffractive coupling in gold nanoparticle arrays and the effect of disorder,” Opt. Lett. 34(4), 401–403 (2009).
[CrossRef] [PubMed]

A. Kinkhabwala, Z. F. Yu, S. H. Fan, Y. Avlasevich, K. Mullen, and W. E. Moerner, “Large single-molecule fluorescence enhancements produced by a bowtie nanoantenna,” Nat. Photonics 3(11), 654–657 (2009).
[CrossRef]

Z. Zhang, A. Weber-Bargioni, S. W. Wu, S. Dhuey, S. Cabrini, and P. J. Schuck, “Manipulating nanoscale light fields with the asymmetric bowtie nano-colorsorter,” Nano Lett. 9(12), 4505–4509 (2009).
[CrossRef] [PubMed]

A. M. Funston, C. Novo, T. J. Davis, and P. Mulvaney, “Plasmon coupling of gold nanorods at short distances and in different geometries,” Nano Lett. 9(4), 1651–1658 (2009).
[CrossRef] [PubMed]

A. V. Kabashin, P. Evans, S. Pastkovsky, W. Hendren, G. A. Wurtz, R. Atkinson, R. Pollard, V. A. Podolskiy, and A. V. Zayats, “Plasmonic nanorod metamaterials for biosensing,” Nat. Mater. 8(11), 867–871 (2009).
[CrossRef] [PubMed]

Y. B. Zheng, Y. W. Yang, L. Jensen, L. Fang, B. K. Juluri, A. H. Flood, P. S. Weiss, J. F. Stoddart, and T. J. Huang, “Active molecular plasmonics: controlling plasmon resonances with molecular switches,” Nano Lett. 9(2), 819–825 (2009).
[CrossRef] [PubMed]

2008

S. Lal, N. K. Grady, J. Kundu, C. S. Levin, J. B. Lassiter, and N. J. Halas, “Tailoring plasmonic substrates for surface enhanced spectroscopies,” Chem. Soc. Rev. 37(5), 898–911 (2008).
[CrossRef] [PubMed]

P. K. Jain and M. A. El-Sayed, “Noble metal nanoparticle pairs: effect of medium for enhanced nanosensing,” Nano Lett. 8(12), 4347–4352 (2008).
[CrossRef]

B. Willingham, D. Brandl, and P. Nordlander, “Plasmon hybridization in nanorod dimmers,” Appl. Phys. B 93(1), 209–216 (2008).
[CrossRef]

J. B. Lassiter, J. Aizpurua, L. I. Hernandez, D. W. Brandl, I. Romero, S. Lal, J. H. Hafner, P. Nordlander, and N. J. Halas, “Close encounters between two nanoshells,” Nano Lett. 8(4), 1212–1218 (2008).
[CrossRef] [PubMed]

2007

E. M. Larsson, J. Alegret, M. Käll, and D. S. Sutherland, “Sensing characteristics of NIR localized surface plasmon resonances in gold nanorings for application as ultrasensitive biosensors,” Nano Lett. 7(5), 1256–1263 (2007).
[CrossRef] [PubMed]

2006

2005

J. Aizpurua, G. W. Bryant, L. J. Richter, F. J. García de Abajo, B. K. Kelley, and T. Mallouk, “Optical properties of coupled metallic nanorods for field-enhanced spectroscopy,” Phys. Rev. B 71(23), 235420 (2005).
[CrossRef]

C. Girard, “Near fields in nanostructures,” Rep. Prog. Phys. 68(8), 1883–1933 (2005).
[CrossRef]

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(8), 1569–1574 (2005).
[CrossRef] [PubMed]

2004

P. Nordlander, C. Oubre, E. Prodan, K. Li, and M. I. Stockman, “Plasmon hybridization in nanoparticle dimmers,” Nano Lett. 4(5), 899–903 (2004).
[CrossRef]

2003

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(1-3), 137–141 (2003).
[CrossRef]

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(5), 057401 (2003).
[CrossRef] [PubMed]

2001

S. A. Maier, M. L. Brongersma, P. G. Kik, S. Meltzer, A. A. G. Requicha, and H. A. Atwater, “Plasmonics - a route to nanoscale optical devices,” Adv. Mater. 13(19), 1501–1505 (2001).
[CrossRef]

1998

F. J. García de Abajo and A. Howie, “Retarded field calculation of electron energy loss in inhomogeneous dielectrics”, Phys. Rev. Lett. 80, 5180–5183 (1998); “Retarded field calculation of electron energy loss in inhomogeneous dielectrics,” Phys. Rev. B 65, 115418 (2002).

1997

K. Kneipp, Y. Wang, H. Kneipp, L. T. Perelman, I. Itzkan, R. R. Dasari, and M. S. Feld, “Single molecule detection using surface-enhanced Raman scattering,” Phys. Rev. Lett. 78(9), 1667–1670 (1997).
[CrossRef]

1972

P. B. Johnson and R. W. Christy, “Optical constants of the nobel metals,” Phys. Rev. B 6(12), 4370–4379 (1972).
[CrossRef]

Aizpurua, J.

J. B. Lassiter, J. Aizpurua, L. I. Hernandez, D. W. Brandl, I. Romero, S. Lal, J. H. Hafner, P. Nordlander, and N. J. Halas, “Close encounters between two nanoshells,” Nano Lett. 8(4), 1212–1218 (2008).
[CrossRef] [PubMed]

I. Romero, J. Aizpurua, G. W. Bryant, and F. J. García De Abajo, “Plasmons in nearly touching metallic nanoparticles: singular response in the limit of touching dimers,” Opt. Express 14(21), 9988–9999 (2006).
[CrossRef] [PubMed]

J. Aizpurua, G. W. Bryant, L. J. Richter, F. J. García de Abajo, B. K. Kelley, and T. Mallouk, “Optical properties of coupled metallic nanorods for field-enhanced spectroscopy,” Phys. Rev. B 71(23), 235420 (2005).
[CrossRef]

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(5), 057401 (2003).
[CrossRef] [PubMed]

Alarcon-Llado, E.

V. K. Lin, S. L. Teo, R. Marty, A. Arbouet, Ch. Girard, E. Alarcon-Llado, S. H. Liu, M. Y. Han, S. Tripathy, and A. Mlayah, “Dual wavelength sensing based on interacting gold nanodisk trimers,” Nanotechnology 21(30), 305501 (2010).
[CrossRef] [PubMed]

Alegret, J.

E. M. Larsson, J. Alegret, M. Käll, and D. S. Sutherland, “Sensing characteristics of NIR localized surface plasmon resonances in gold nanorings for application as ultrasensitive biosensors,” Nano Lett. 7(5), 1256–1263 (2007).
[CrossRef] [PubMed]

Alivisatos, A. P.

M. Hentschel, M. Saliba, R. Vogelgesang, H. Giessen, A. P. Alivisatos, and N. Liu, “Transition from isolated to collective modes in plasmonic oligomers,” Nano Lett. 10(7), 2721–2726 (2010).
[CrossRef] [PubMed]

Arbouet, A.

V. K. Lin, S. L. Teo, R. Marty, A. Arbouet, Ch. Girard, E. Alarcon-Llado, S. H. Liu, M. Y. Han, S. Tripathy, and A. Mlayah, “Dual wavelength sensing based on interacting gold nanodisk trimers,” Nanotechnology 21(30), 305501 (2010).
[CrossRef] [PubMed]

Atkinson, R.

A. V. Kabashin, P. Evans, S. Pastkovsky, W. Hendren, G. A. Wurtz, R. Atkinson, R. Pollard, V. A. Podolskiy, and A. V. Zayats, “Plasmonic nanorod metamaterials for biosensing,” Nat. Mater. 8(11), 867–871 (2009).
[CrossRef] [PubMed]

Atwater, H. A.

S. A. Maier, M. L. Brongersma, P. G. Kik, S. Meltzer, A. A. G. Requicha, and H. A. Atwater, “Plasmonics - a route to nanoscale optical devices,” Adv. Mater. 13(19), 1501–1505 (2001).
[CrossRef]

Auguié, B.

Aussenegg, F. R.

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(1-3), 137–141 (2003).
[CrossRef]

Avlasevich, Y.

A. Kinkhabwala, Z. F. Yu, S. H. Fan, Y. Avlasevich, K. Mullen, and W. E. Moerner, “Large single-molecule fluorescence enhancements produced by a bowtie nanoantenna,” Nat. Photonics 3(11), 654–657 (2009).
[CrossRef]

Banaee, M. G.

Bao, J.

J. A. Fan, C. H. Wu, K. Bao, J. Bao, R. Bardhan, N. J. Halas, V. N. Manoharan, P. Nordlander, G. Shvets, and F. Capasso, “Self-assembled plasmonic nanoparticle clusters,” Science 328(5982), 1135–1138 (2010).
[CrossRef] [PubMed]

Bao, K.

J. A. Fan, C. H. Wu, K. Bao, J. Bao, R. Bardhan, N. J. Halas, V. N. Manoharan, P. Nordlander, G. Shvets, and F. Capasso, “Self-assembled plasmonic nanoparticle clusters,” Science 328(5982), 1135–1138 (2010).
[CrossRef] [PubMed]

Bardhan, R.

J. A. Fan, C. H. Wu, K. Bao, J. Bao, R. Bardhan, N. J. Halas, V. N. Manoharan, P. Nordlander, G. Shvets, and F. Capasso, “Self-assembled plasmonic nanoparticle clusters,” Science 328(5982), 1135–1138 (2010).
[CrossRef] [PubMed]

Barnes, W. L.

Brandl, D.

B. Willingham, D. Brandl, and P. Nordlander, “Plasmon hybridization in nanorod dimmers,” Appl. Phys. B 93(1), 209–216 (2008).
[CrossRef]

Brandl, D. W.

J. B. Lassiter, J. Aizpurua, L. I. Hernandez, D. W. Brandl, I. Romero, S. Lal, J. H. Hafner, P. Nordlander, and N. J. Halas, “Close encounters between two nanoshells,” Nano Lett. 8(4), 1212–1218 (2008).
[CrossRef] [PubMed]

Brongersma, M. L.

S. A. Maier, M. L. Brongersma, P. G. Kik, S. Meltzer, A. A. G. Requicha, and H. A. Atwater, “Plasmonics - a route to nanoscale optical devices,” Adv. Mater. 13(19), 1501–1505 (2001).
[CrossRef]

Bryant, G. W.

I. Romero, J. Aizpurua, G. W. Bryant, and F. J. García De Abajo, “Plasmons in nearly touching metallic nanoparticles: singular response in the limit of touching dimers,” Opt. Express 14(21), 9988–9999 (2006).
[CrossRef] [PubMed]

J. Aizpurua, G. W. Bryant, L. J. Richter, F. J. García de Abajo, B. K. Kelley, and T. Mallouk, “Optical properties of coupled metallic nanorods for field-enhanced spectroscopy,” Phys. Rev. B 71(23), 235420 (2005).
[CrossRef]

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(5), 057401 (2003).
[CrossRef] [PubMed]

Cabrini, S.

Z. Zhang, A. Weber-Bargioni, S. W. Wu, S. Dhuey, S. Cabrini, and P. J. Schuck, “Manipulating nanoscale light fields with the asymmetric bowtie nano-colorsorter,” Nano Lett. 9(12), 4505–4509 (2009).
[CrossRef] [PubMed]

Capasso, F.

J. A. Fan, C. H. Wu, K. Bao, J. Bao, R. Bardhan, N. J. Halas, V. N. Manoharan, P. Nordlander, G. Shvets, and F. Capasso, “Self-assembled plasmonic nanoparticle clusters,” Science 328(5982), 1135–1138 (2010).
[CrossRef] [PubMed]

J. B. Lassiter, H. Sobhani, J. A. Fan, J. Kundu, F. Capasso, P. Nordlander, and N. J. Halas, “Fano resonances in plasmonic nanoclusters: geometrical and chemical tunability,” Nano Lett. 10(8), 3184–3189 (2010).
[CrossRef] [PubMed]

Christy, R. W.

P. B. Johnson and R. W. Christy, “Optical constants of the nobel metals,” Phys. Rev. B 6(12), 4370–4379 (1972).
[CrossRef]

Crozier, K. B.

Dasari, R. R.

K. Kneipp, Y. Wang, H. Kneipp, L. T. Perelman, I. Itzkan, R. R. Dasari, and M. S. Feld, “Single molecule detection using surface-enhanced Raman scattering,” Phys. Rev. Lett. 78(9), 1667–1670 (1997).
[CrossRef]

Davis, T. J.

A. M. Funston, C. Novo, T. J. Davis, and P. Mulvaney, “Plasmon coupling of gold nanorods at short distances and in different geometries,” Nano Lett. 9(4), 1651–1658 (2009).
[CrossRef] [PubMed]

Dhuey, S.

Z. Zhang, A. Weber-Bargioni, S. W. Wu, S. Dhuey, S. Cabrini, and P. J. Schuck, “Manipulating nanoscale light fields with the asymmetric bowtie nano-colorsorter,” Nano Lett. 9(12), 4505–4509 (2009).
[CrossRef] [PubMed]

El-Sayed, M. A.

P. K. Jain and M. A. El-Sayed, “Noble metal nanoparticle pairs: effect of medium for enhanced nanosensing,” Nano Lett. 8(12), 4347–4352 (2008).
[CrossRef]

Evans, P.

A. V. Kabashin, P. Evans, S. Pastkovsky, W. Hendren, G. A. Wurtz, R. Atkinson, R. Pollard, V. A. Podolskiy, and A. V. Zayats, “Plasmonic nanorod metamaterials for biosensing,” Nat. Mater. 8(11), 867–871 (2009).
[CrossRef] [PubMed]

Fan, J. A.

J. A. Fan, C. H. Wu, K. Bao, J. Bao, R. Bardhan, N. J. Halas, V. N. Manoharan, P. Nordlander, G. Shvets, and F. Capasso, “Self-assembled plasmonic nanoparticle clusters,” Science 328(5982), 1135–1138 (2010).
[CrossRef] [PubMed]

J. B. Lassiter, H. Sobhani, J. A. Fan, J. Kundu, F. Capasso, P. Nordlander, and N. J. Halas, “Fano resonances in plasmonic nanoclusters: geometrical and chemical tunability,” Nano Lett. 10(8), 3184–3189 (2010).
[CrossRef] [PubMed]

Fan, S. H.

A. Kinkhabwala, Z. F. Yu, S. H. Fan, Y. Avlasevich, K. Mullen, and W. E. Moerner, “Large single-molecule fluorescence enhancements produced by a bowtie nanoantenna,” Nat. Photonics 3(11), 654–657 (2009).
[CrossRef]

Fang, L.

Y. B. Zheng, Y. W. Yang, L. Jensen, L. Fang, B. K. Juluri, A. H. Flood, P. S. Weiss, J. F. Stoddart, and T. J. Huang, “Active molecular plasmonics: controlling plasmon resonances with molecular switches,” Nano Lett. 9(2), 819–825 (2009).
[CrossRef] [PubMed]

Feld, M. S.

K. Kneipp, Y. Wang, H. Kneipp, L. T. Perelman, I. Itzkan, R. R. Dasari, and M. S. Feld, “Single molecule detection using surface-enhanced Raman scattering,” Phys. Rev. Lett. 78(9), 1667–1670 (1997).
[CrossRef]

Flood, A. H.

Y. B. Zheng, Y. W. Yang, L. Jensen, L. Fang, B. K. Juluri, A. H. Flood, P. S. Weiss, J. F. Stoddart, and T. J. Huang, “Active molecular plasmonics: controlling plasmon resonances with molecular switches,” Nano Lett. 9(2), 819–825 (2009).
[CrossRef] [PubMed]

Freeman, R. G.

K. L. Wustholz, A. I. Henry, J. M. McMahon, R. G. Freeman, N. Valley, M. E. Piotti, M. J. Natan, G. C. Schatz, and R. P. Van Duyne, “Structure-activity relationships in gold nanoparticle dimers and trimers for surface-enhanced Raman spectroscopy,” J. Am. Chem. Soc. 132(31), 10903–10910 (2010).
[CrossRef] [PubMed]

Funston, A. M.

A. M. Funston, C. Novo, T. J. Davis, and P. Mulvaney, “Plasmon coupling of gold nanorods at short distances and in different geometries,” Nano Lett. 9(4), 1651–1658 (2009).
[CrossRef] [PubMed]

García De Abajo, F. J.

I. Romero, J. Aizpurua, G. W. Bryant, and F. J. García De Abajo, “Plasmons in nearly touching metallic nanoparticles: singular response in the limit of touching dimers,” Opt. Express 14(21), 9988–9999 (2006).
[CrossRef] [PubMed]

J. Aizpurua, G. W. Bryant, L. J. Richter, F. J. García de Abajo, B. K. Kelley, and T. Mallouk, “Optical properties of coupled metallic nanorods for field-enhanced spectroscopy,” Phys. Rev. B 71(23), 235420 (2005).
[CrossRef]

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(5), 057401 (2003).
[CrossRef] [PubMed]

F. J. García de Abajo and A. Howie, “Retarded field calculation of electron energy loss in inhomogeneous dielectrics”, Phys. Rev. Lett. 80, 5180–5183 (1998); “Retarded field calculation of electron energy loss in inhomogeneous dielectrics,” Phys. Rev. B 65, 115418 (2002).

Giessen, H.

M. Hentschel, M. Saliba, R. Vogelgesang, H. Giessen, A. P. Alivisatos, and N. Liu, “Transition from isolated to collective modes in plasmonic oligomers,” Nano Lett. 10(7), 2721–2726 (2010).
[CrossRef] [PubMed]

Girard, C.

C. Girard, “Near fields in nanostructures,” Rep. Prog. Phys. 68(8), 1883–1933 (2005).
[CrossRef]

Girard, Ch.

V. K. Lin, S. L. Teo, R. Marty, A. Arbouet, Ch. Girard, E. Alarcon-Llado, S. H. Liu, M. Y. Han, S. Tripathy, and A. Mlayah, “Dual wavelength sensing based on interacting gold nanodisk trimers,” Nanotechnology 21(30), 305501 (2010).
[CrossRef] [PubMed]

Grady, N. K.

S. Lal, N. K. Grady, J. Kundu, C. S. Levin, J. B. Lassiter, and N. J. Halas, “Tailoring plasmonic substrates for surface enhanced spectroscopies,” Chem. Soc. Rev. 37(5), 898–911 (2008).
[CrossRef] [PubMed]

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(8), 1569–1574 (2005).
[CrossRef] [PubMed]

Hafner, J. H.

J. B. Lassiter, J. Aizpurua, L. I. Hernandez, D. W. Brandl, I. Romero, S. Lal, J. H. Hafner, P. Nordlander, and N. J. Halas, “Close encounters between two nanoshells,” Nano Lett. 8(4), 1212–1218 (2008).
[CrossRef] [PubMed]

Halas, N. J.

J. B. Lassiter, H. Sobhani, J. A. Fan, J. Kundu, F. Capasso, P. Nordlander, and N. J. Halas, “Fano resonances in plasmonic nanoclusters: geometrical and chemical tunability,” Nano Lett. 10(8), 3184–3189 (2010).
[CrossRef] [PubMed]

J. A. Fan, C. H. Wu, K. Bao, J. Bao, R. Bardhan, N. J. Halas, V. N. Manoharan, P. Nordlander, G. Shvets, and F. Capasso, “Self-assembled plasmonic nanoparticle clusters,” Science 328(5982), 1135–1138 (2010).
[CrossRef] [PubMed]

S. Lal, N. K. Grady, J. Kundu, C. S. Levin, J. B. Lassiter, and N. J. Halas, “Tailoring plasmonic substrates for surface enhanced spectroscopies,” Chem. Soc. Rev. 37(5), 898–911 (2008).
[CrossRef] [PubMed]

J. B. Lassiter, J. Aizpurua, L. I. Hernandez, D. W. Brandl, I. Romero, S. Lal, J. H. Hafner, P. Nordlander, and N. J. Halas, “Close encounters between two nanoshells,” Nano Lett. 8(4), 1212–1218 (2008).
[CrossRef] [PubMed]

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(8), 1569–1574 (2005).
[CrossRef] [PubMed]

Han, M. Y.

V. K. Lin, S. L. Teo, R. Marty, A. Arbouet, Ch. Girard, E. Alarcon-Llado, S. H. Liu, M. Y. Han, S. Tripathy, and A. Mlayah, “Dual wavelength sensing based on interacting gold nanodisk trimers,” Nanotechnology 21(30), 305501 (2010).
[CrossRef] [PubMed]

Hanarp, P.

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(5), 057401 (2003).
[CrossRef] [PubMed]

Hendren, W.

A. V. Kabashin, P. Evans, S. Pastkovsky, W. Hendren, G. A. Wurtz, R. Atkinson, R. Pollard, V. A. Podolskiy, and A. V. Zayats, “Plasmonic nanorod metamaterials for biosensing,” Nat. Mater. 8(11), 867–871 (2009).
[CrossRef] [PubMed]

Henry, A. I.

K. L. Wustholz, A. I. Henry, J. M. McMahon, R. G. Freeman, N. Valley, M. E. Piotti, M. J. Natan, G. C. Schatz, and R. P. Van Duyne, “Structure-activity relationships in gold nanoparticle dimers and trimers for surface-enhanced Raman spectroscopy,” J. Am. Chem. Soc. 132(31), 10903–10910 (2010).
[CrossRef] [PubMed]

Hentschel, M.

M. Hentschel, M. Saliba, R. Vogelgesang, H. Giessen, A. P. Alivisatos, and N. Liu, “Transition from isolated to collective modes in plasmonic oligomers,” Nano Lett. 10(7), 2721–2726 (2010).
[CrossRef] [PubMed]

Hernandez, L. I.

J. B. Lassiter, J. Aizpurua, L. I. Hernandez, D. W. Brandl, I. Romero, S. Lal, J. H. Hafner, P. Nordlander, and N. J. Halas, “Close encounters between two nanoshells,” Nano Lett. 8(4), 1212–1218 (2008).
[CrossRef] [PubMed]

Hohenau, A.

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(1-3), 137–141 (2003).
[CrossRef]

Hollars, C. W.

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(8), 1569–1574 (2005).
[CrossRef] [PubMed]

Howie, A.

F. J. García de Abajo and A. Howie, “Retarded field calculation of electron energy loss in inhomogeneous dielectrics”, Phys. Rev. Lett. 80, 5180–5183 (1998); “Retarded field calculation of electron energy loss in inhomogeneous dielectrics,” Phys. Rev. B 65, 115418 (2002).

Huang, T. J.

Y. B. Zheng, Y. W. Yang, L. Jensen, L. Fang, B. K. Juluri, A. H. Flood, P. S. Weiss, J. F. Stoddart, and T. J. Huang, “Active molecular plasmonics: controlling plasmon resonances with molecular switches,” Nano Lett. 9(2), 819–825 (2009).
[CrossRef] [PubMed]

Huser, T. R.

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(8), 1569–1574 (2005).
[CrossRef] [PubMed]

Itzkan, I.

K. Kneipp, Y. Wang, H. Kneipp, L. T. Perelman, I. Itzkan, R. R. Dasari, and M. S. Feld, “Single molecule detection using surface-enhanced Raman scattering,” Phys. Rev. Lett. 78(9), 1667–1670 (1997).
[CrossRef]

Jackson, J. B.

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(8), 1569–1574 (2005).
[CrossRef] [PubMed]

Jain, P. K.

P. K. Jain and M. A. El-Sayed, “Noble metal nanoparticle pairs: effect of medium for enhanced nanosensing,” Nano Lett. 8(12), 4347–4352 (2008).
[CrossRef]

Jensen, L.

Y. B. Zheng, Y. W. Yang, L. Jensen, L. Fang, B. K. Juluri, A. H. Flood, P. S. Weiss, J. F. Stoddart, and T. J. Huang, “Active molecular plasmonics: controlling plasmon resonances with molecular switches,” Nano Lett. 9(2), 819–825 (2009).
[CrossRef] [PubMed]

Johnson, P. B.

P. B. Johnson and R. W. Christy, “Optical constants of the nobel metals,” Phys. Rev. B 6(12), 4370–4379 (1972).
[CrossRef]

Juluri, B. K.

Y. B. Zheng, Y. W. Yang, L. Jensen, L. Fang, B. K. Juluri, A. H. Flood, P. S. Weiss, J. F. Stoddart, and T. J. Huang, “Active molecular plasmonics: controlling plasmon resonances with molecular switches,” Nano Lett. 9(2), 819–825 (2009).
[CrossRef] [PubMed]

Kabashin, A. V.

A. V. Kabashin, P. Evans, S. Pastkovsky, W. Hendren, G. A. Wurtz, R. Atkinson, R. Pollard, V. A. Podolskiy, and A. V. Zayats, “Plasmonic nanorod metamaterials for biosensing,” Nat. Mater. 8(11), 867–871 (2009).
[CrossRef] [PubMed]

Käll, M.

E. M. Larsson, J. Alegret, M. Käll, and D. S. Sutherland, “Sensing characteristics of NIR localized surface plasmon resonances in gold nanorings for application as ultrasensitive biosensors,” Nano Lett. 7(5), 1256–1263 (2007).
[CrossRef] [PubMed]

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(5), 057401 (2003).
[CrossRef] [PubMed]

Kelley, B. K.

J. Aizpurua, G. W. Bryant, L. J. Richter, F. J. García de Abajo, B. K. Kelley, and T. Mallouk, “Optical properties of coupled metallic nanorods for field-enhanced spectroscopy,” Phys. Rev. B 71(23), 235420 (2005).
[CrossRef]

Kik, P. G.

S. A. Maier, M. L. Brongersma, P. G. Kik, S. Meltzer, A. A. G. Requicha, and H. A. Atwater, “Plasmonics - a route to nanoscale optical devices,” Adv. Mater. 13(19), 1501–1505 (2001).
[CrossRef]

Kinkhabwala, A.

A. Kinkhabwala, Z. F. Yu, S. H. Fan, Y. Avlasevich, K. Mullen, and W. E. Moerner, “Large single-molecule fluorescence enhancements produced by a bowtie nanoantenna,” Nat. Photonics 3(11), 654–657 (2009).
[CrossRef]

Kneipp, H.

K. Kneipp, Y. Wang, H. Kneipp, L. T. Perelman, I. Itzkan, R. R. Dasari, and M. S. Feld, “Single molecule detection using surface-enhanced Raman scattering,” Phys. Rev. Lett. 78(9), 1667–1670 (1997).
[CrossRef]

Kneipp, K.

K. Kneipp, Y. Wang, H. Kneipp, L. T. Perelman, I. Itzkan, R. R. Dasari, and M. S. Feld, “Single molecule detection using surface-enhanced Raman scattering,” Phys. Rev. Lett. 78(9), 1667–1670 (1997).
[CrossRef]

Krenn, J. R.

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(1-3), 137–141 (2003).
[CrossRef]

Kundu, J.

J. B. Lassiter, H. Sobhani, J. A. Fan, J. Kundu, F. Capasso, P. Nordlander, and N. J. Halas, “Fano resonances in plasmonic nanoclusters: geometrical and chemical tunability,” Nano Lett. 10(8), 3184–3189 (2010).
[CrossRef] [PubMed]

S. Lal, N. K. Grady, J. Kundu, C. S. Levin, J. B. Lassiter, and N. J. Halas, “Tailoring plasmonic substrates for surface enhanced spectroscopies,” Chem. Soc. Rev. 37(5), 898–911 (2008).
[CrossRef] [PubMed]

Lal, S.

S. Lal, N. K. Grady, J. Kundu, C. S. Levin, J. B. Lassiter, and N. J. Halas, “Tailoring plasmonic substrates for surface enhanced spectroscopies,” Chem. Soc. Rev. 37(5), 898–911 (2008).
[CrossRef] [PubMed]

J. B. Lassiter, J. Aizpurua, L. I. Hernandez, D. W. Brandl, I. Romero, S. Lal, J. H. Hafner, P. Nordlander, and N. J. Halas, “Close encounters between two nanoshells,” Nano Lett. 8(4), 1212–1218 (2008).
[CrossRef] [PubMed]

Lamprecht, B.

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(1-3), 137–141 (2003).
[CrossRef]

Lane, S. M.

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(8), 1569–1574 (2005).
[CrossRef] [PubMed]

Larsson, E. M.

E. M. Larsson, J. Alegret, M. Käll, and D. S. Sutherland, “Sensing characteristics of NIR localized surface plasmon resonances in gold nanorings for application as ultrasensitive biosensors,” Nano Lett. 7(5), 1256–1263 (2007).
[CrossRef] [PubMed]

Lassiter, J. B.

J. B. Lassiter, H. Sobhani, J. A. Fan, J. Kundu, F. Capasso, P. Nordlander, and N. J. Halas, “Fano resonances in plasmonic nanoclusters: geometrical and chemical tunability,” Nano Lett. 10(8), 3184–3189 (2010).
[CrossRef] [PubMed]

S. Lal, N. K. Grady, J. Kundu, C. S. Levin, J. B. Lassiter, and N. J. Halas, “Tailoring plasmonic substrates for surface enhanced spectroscopies,” Chem. Soc. Rev. 37(5), 898–911 (2008).
[CrossRef] [PubMed]

J. B. Lassiter, J. Aizpurua, L. I. Hernandez, D. W. Brandl, I. Romero, S. Lal, J. H. Hafner, P. Nordlander, and N. J. Halas, “Close encounters between two nanoshells,” Nano Lett. 8(4), 1212–1218 (2008).
[CrossRef] [PubMed]

Leitner, A.

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(1-3), 137–141 (2003).
[CrossRef]

Levin, C. S.

S. Lal, N. K. Grady, J. Kundu, C. S. Levin, J. B. Lassiter, and N. J. Halas, “Tailoring plasmonic substrates for surface enhanced spectroscopies,” Chem. Soc. Rev. 37(5), 898–911 (2008).
[CrossRef] [PubMed]

Li, K.

P. Nordlander, C. Oubre, E. Prodan, K. Li, and M. I. Stockman, “Plasmon hybridization in nanoparticle dimmers,” Nano Lett. 4(5), 899–903 (2004).
[CrossRef]

Lin, V. K.

V. K. Lin, S. L. Teo, R. Marty, A. Arbouet, Ch. Girard, E. Alarcon-Llado, S. H. Liu, M. Y. Han, S. Tripathy, and A. Mlayah, “Dual wavelength sensing based on interacting gold nanodisk trimers,” Nanotechnology 21(30), 305501 (2010).
[CrossRef] [PubMed]

Liu, N.

M. Hentschel, M. Saliba, R. Vogelgesang, H. Giessen, A. P. Alivisatos, and N. Liu, “Transition from isolated to collective modes in plasmonic oligomers,” Nano Lett. 10(7), 2721–2726 (2010).
[CrossRef] [PubMed]

Liu, S. H.

V. K. Lin, S. L. Teo, R. Marty, A. Arbouet, Ch. Girard, E. Alarcon-Llado, S. H. Liu, M. Y. Han, S. Tripathy, and A. Mlayah, “Dual wavelength sensing based on interacting gold nanodisk trimers,” Nanotechnology 21(30), 305501 (2010).
[CrossRef] [PubMed]

Maier, S. A.

S. A. Maier, M. L. Brongersma, P. G. Kik, S. Meltzer, A. A. G. Requicha, and H. A. Atwater, “Plasmonics - a route to nanoscale optical devices,” Adv. Mater. 13(19), 1501–1505 (2001).
[CrossRef]

Mallouk, T.

J. Aizpurua, G. W. Bryant, L. J. Richter, F. J. García de Abajo, B. K. Kelley, and T. Mallouk, “Optical properties of coupled metallic nanorods for field-enhanced spectroscopy,” Phys. Rev. B 71(23), 235420 (2005).
[CrossRef]

Manoharan, V. N.

J. A. Fan, C. H. Wu, K. Bao, J. Bao, R. Bardhan, N. J. Halas, V. N. Manoharan, P. Nordlander, G. Shvets, and F. Capasso, “Self-assembled plasmonic nanoparticle clusters,” Science 328(5982), 1135–1138 (2010).
[CrossRef] [PubMed]

Marty, R.

V. K. Lin, S. L. Teo, R. Marty, A. Arbouet, Ch. Girard, E. Alarcon-Llado, S. H. Liu, M. Y. Han, S. Tripathy, and A. Mlayah, “Dual wavelength sensing based on interacting gold nanodisk trimers,” Nanotechnology 21(30), 305501 (2010).
[CrossRef] [PubMed]

McMahon, J. M.

K. L. Wustholz, A. I. Henry, J. M. McMahon, R. G. Freeman, N. Valley, M. E. Piotti, M. J. Natan, G. C. Schatz, and R. P. Van Duyne, “Structure-activity relationships in gold nanoparticle dimers and trimers for surface-enhanced Raman spectroscopy,” J. Am. Chem. Soc. 132(31), 10903–10910 (2010).
[CrossRef] [PubMed]

Meltzer, S.

S. A. Maier, M. L. Brongersma, P. G. Kik, S. Meltzer, A. A. G. Requicha, and H. A. Atwater, “Plasmonics - a route to nanoscale optical devices,” Adv. Mater. 13(19), 1501–1505 (2001).
[CrossRef]

Mlayah, A.

V. K. Lin, S. L. Teo, R. Marty, A. Arbouet, Ch. Girard, E. Alarcon-Llado, S. H. Liu, M. Y. Han, S. Tripathy, and A. Mlayah, “Dual wavelength sensing based on interacting gold nanodisk trimers,” Nanotechnology 21(30), 305501 (2010).
[CrossRef] [PubMed]

Moerner, W. E.

A. Kinkhabwala, Z. F. Yu, S. H. Fan, Y. Avlasevich, K. Mullen, and W. E. Moerner, “Large single-molecule fluorescence enhancements produced by a bowtie nanoantenna,” Nat. Photonics 3(11), 654–657 (2009).
[CrossRef]

Mullen, K.

A. Kinkhabwala, Z. F. Yu, S. H. Fan, Y. Avlasevich, K. Mullen, and W. E. Moerner, “Large single-molecule fluorescence enhancements produced by a bowtie nanoantenna,” Nat. Photonics 3(11), 654–657 (2009).
[CrossRef]

Mulvaney, P.

A. M. Funston, C. Novo, T. J. Davis, and P. Mulvaney, “Plasmon coupling of gold nanorods at short distances and in different geometries,” Nano Lett. 9(4), 1651–1658 (2009).
[CrossRef] [PubMed]

Natan, M. J.

K. L. Wustholz, A. I. Henry, J. M. McMahon, R. G. Freeman, N. Valley, M. E. Piotti, M. J. Natan, G. C. Schatz, and R. P. Van Duyne, “Structure-activity relationships in gold nanoparticle dimers and trimers for surface-enhanced Raman spectroscopy,” J. Am. Chem. Soc. 132(31), 10903–10910 (2010).
[CrossRef] [PubMed]

Nordlander, P.

J. B. Lassiter, H. Sobhani, J. A. Fan, J. Kundu, F. Capasso, P. Nordlander, and N. J. Halas, “Fano resonances in plasmonic nanoclusters: geometrical and chemical tunability,” Nano Lett. 10(8), 3184–3189 (2010).
[CrossRef] [PubMed]

J. A. Fan, C. H. Wu, K. Bao, J. Bao, R. Bardhan, N. J. Halas, V. N. Manoharan, P. Nordlander, G. Shvets, and F. Capasso, “Self-assembled plasmonic nanoparticle clusters,” Science 328(5982), 1135–1138 (2010).
[CrossRef] [PubMed]

B. Willingham, D. Brandl, and P. Nordlander, “Plasmon hybridization in nanorod dimmers,” Appl. Phys. B 93(1), 209–216 (2008).
[CrossRef]

J. B. Lassiter, J. Aizpurua, L. I. Hernandez, D. W. Brandl, I. Romero, S. Lal, J. H. Hafner, P. Nordlander, and N. J. Halas, “Close encounters between two nanoshells,” Nano Lett. 8(4), 1212–1218 (2008).
[CrossRef] [PubMed]

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(8), 1569–1574 (2005).
[CrossRef] [PubMed]

P. Nordlander, C. Oubre, E. Prodan, K. Li, and M. I. Stockman, “Plasmon hybridization in nanoparticle dimmers,” Nano Lett. 4(5), 899–903 (2004).
[CrossRef]

Novo, C.

A. M. Funston, C. Novo, T. J. Davis, and P. Mulvaney, “Plasmon coupling of gold nanorods at short distances and in different geometries,” Nano Lett. 9(4), 1651–1658 (2009).
[CrossRef] [PubMed]

Oubre, C.

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(8), 1569–1574 (2005).
[CrossRef] [PubMed]

P. Nordlander, C. Oubre, E. Prodan, K. Li, and M. I. Stockman, “Plasmon hybridization in nanoparticle dimmers,” Nano Lett. 4(5), 899–903 (2004).
[CrossRef]

Pastkovsky, S.

A. V. Kabashin, P. Evans, S. Pastkovsky, W. Hendren, G. A. Wurtz, R. Atkinson, R. Pollard, V. A. Podolskiy, and A. V. Zayats, “Plasmonic nanorod metamaterials for biosensing,” Nat. Mater. 8(11), 867–871 (2009).
[CrossRef] [PubMed]

Perelman, L. T.

K. Kneipp, Y. Wang, H. Kneipp, L. T. Perelman, I. Itzkan, R. R. Dasari, and M. S. Feld, “Single molecule detection using surface-enhanced Raman scattering,” Phys. Rev. Lett. 78(9), 1667–1670 (1997).
[CrossRef]

Piotti, M. E.

K. L. Wustholz, A. I. Henry, J. M. McMahon, R. G. Freeman, N. Valley, M. E. Piotti, M. J. Natan, G. C. Schatz, and R. P. Van Duyne, “Structure-activity relationships in gold nanoparticle dimers and trimers for surface-enhanced Raman spectroscopy,” J. Am. Chem. Soc. 132(31), 10903–10910 (2010).
[CrossRef] [PubMed]

Podolskiy, V. A.

A. V. Kabashin, P. Evans, S. Pastkovsky, W. Hendren, G. A. Wurtz, R. Atkinson, R. Pollard, V. A. Podolskiy, and A. V. Zayats, “Plasmonic nanorod metamaterials for biosensing,” Nat. Mater. 8(11), 867–871 (2009).
[CrossRef] [PubMed]

Pollard, R.

A. V. Kabashin, P. Evans, S. Pastkovsky, W. Hendren, G. A. Wurtz, R. Atkinson, R. Pollard, V. A. Podolskiy, and A. V. Zayats, “Plasmonic nanorod metamaterials for biosensing,” Nat. Mater. 8(11), 867–871 (2009).
[CrossRef] [PubMed]

Prodan, E.

P. Nordlander, C. Oubre, E. Prodan, K. Li, and M. I. Stockman, “Plasmon hybridization in nanoparticle dimmers,” Nano Lett. 4(5), 899–903 (2004).
[CrossRef]

Rechberger, W.

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(1-3), 137–141 (2003).
[CrossRef]

Requicha, A. A. G.

S. A. Maier, M. L. Brongersma, P. G. Kik, S. Meltzer, A. A. G. Requicha, and H. A. Atwater, “Plasmonics - a route to nanoscale optical devices,” Adv. Mater. 13(19), 1501–1505 (2001).
[CrossRef]

Richter, L. J.

J. Aizpurua, G. W. Bryant, L. J. Richter, F. J. García de Abajo, B. K. Kelley, and T. Mallouk, “Optical properties of coupled metallic nanorods for field-enhanced spectroscopy,” Phys. Rev. B 71(23), 235420 (2005).
[CrossRef]

Romero, I.

J. B. Lassiter, J. Aizpurua, L. I. Hernandez, D. W. Brandl, I. Romero, S. Lal, J. H. Hafner, P. Nordlander, and N. J. Halas, “Close encounters between two nanoshells,” Nano Lett. 8(4), 1212–1218 (2008).
[CrossRef] [PubMed]

I. Romero, J. Aizpurua, G. W. Bryant, and F. J. García De Abajo, “Plasmons in nearly touching metallic nanoparticles: singular response in the limit of touching dimers,” Opt. Express 14(21), 9988–9999 (2006).
[CrossRef] [PubMed]

Saliba, M.

M. Hentschel, M. Saliba, R. Vogelgesang, H. Giessen, A. P. Alivisatos, and N. Liu, “Transition from isolated to collective modes in plasmonic oligomers,” Nano Lett. 10(7), 2721–2726 (2010).
[CrossRef] [PubMed]

Schatz, G. C.

K. L. Wustholz, A. I. Henry, J. M. McMahon, R. G. Freeman, N. Valley, M. E. Piotti, M. J. Natan, G. C. Schatz, and R. P. Van Duyne, “Structure-activity relationships in gold nanoparticle dimers and trimers for surface-enhanced Raman spectroscopy,” J. Am. Chem. Soc. 132(31), 10903–10910 (2010).
[CrossRef] [PubMed]

Schuck, P. J.

Z. Zhang, A. Weber-Bargioni, S. W. Wu, S. Dhuey, S. Cabrini, and P. J. Schuck, “Manipulating nanoscale light fields with the asymmetric bowtie nano-colorsorter,” Nano Lett. 9(12), 4505–4509 (2009).
[CrossRef] [PubMed]

Shvets, G.

J. A. Fan, C. H. Wu, K. Bao, J. Bao, R. Bardhan, N. J. Halas, V. N. Manoharan, P. Nordlander, G. Shvets, and F. Capasso, “Self-assembled plasmonic nanoparticle clusters,” Science 328(5982), 1135–1138 (2010).
[CrossRef] [PubMed]

Sobhani, H.

J. B. Lassiter, H. Sobhani, J. A. Fan, J. Kundu, F. Capasso, P. Nordlander, and N. J. Halas, “Fano resonances in plasmonic nanoclusters: geometrical and chemical tunability,” Nano Lett. 10(8), 3184–3189 (2010).
[CrossRef] [PubMed]

Stockman, M. I.

P. Nordlander, C. Oubre, E. Prodan, K. Li, and M. I. Stockman, “Plasmon hybridization in nanoparticle dimmers,” Nano Lett. 4(5), 899–903 (2004).
[CrossRef]

Stoddart, J. F.

Y. B. Zheng, Y. W. Yang, L. Jensen, L. Fang, B. K. Juluri, A. H. Flood, P. S. Weiss, J. F. Stoddart, and T. J. Huang, “Active molecular plasmonics: controlling plasmon resonances with molecular switches,” Nano Lett. 9(2), 819–825 (2009).
[CrossRef] [PubMed]

Sutherland, D. S.

E. M. Larsson, J. Alegret, M. Käll, and D. S. Sutherland, “Sensing characteristics of NIR localized surface plasmon resonances in gold nanorings for application as ultrasensitive biosensors,” Nano Lett. 7(5), 1256–1263 (2007).
[CrossRef] [PubMed]

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(5), 057401 (2003).
[CrossRef] [PubMed]

Talley, C. E.

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(8), 1569–1574 (2005).
[CrossRef] [PubMed]

Teo, S. L.

V. K. Lin, S. L. Teo, R. Marty, A. Arbouet, Ch. Girard, E. Alarcon-Llado, S. H. Liu, M. Y. Han, S. Tripathy, and A. Mlayah, “Dual wavelength sensing based on interacting gold nanodisk trimers,” Nanotechnology 21(30), 305501 (2010).
[CrossRef] [PubMed]

Tripathy, S.

V. K. Lin, S. L. Teo, R. Marty, A. Arbouet, Ch. Girard, E. Alarcon-Llado, S. H. Liu, M. Y. Han, S. Tripathy, and A. Mlayah, “Dual wavelength sensing based on interacting gold nanodisk trimers,” Nanotechnology 21(30), 305501 (2010).
[CrossRef] [PubMed]

Valley, N.

K. L. Wustholz, A. I. Henry, J. M. McMahon, R. G. Freeman, N. Valley, M. E. Piotti, M. J. Natan, G. C. Schatz, and R. P. Van Duyne, “Structure-activity relationships in gold nanoparticle dimers and trimers for surface-enhanced Raman spectroscopy,” J. Am. Chem. Soc. 132(31), 10903–10910 (2010).
[CrossRef] [PubMed]

Van Duyne, R. P.

K. L. Wustholz, A. I. Henry, J. M. McMahon, R. G. Freeman, N. Valley, M. E. Piotti, M. J. Natan, G. C. Schatz, and R. P. Van Duyne, “Structure-activity relationships in gold nanoparticle dimers and trimers for surface-enhanced Raman spectroscopy,” J. Am. Chem. Soc. 132(31), 10903–10910 (2010).
[CrossRef] [PubMed]

Vogelgesang, R.

M. Hentschel, M. Saliba, R. Vogelgesang, H. Giessen, A. P. Alivisatos, and N. Liu, “Transition from isolated to collective modes in plasmonic oligomers,” Nano Lett. 10(7), 2721–2726 (2010).
[CrossRef] [PubMed]

Wang, Y.

K. Kneipp, Y. Wang, H. Kneipp, L. T. Perelman, I. Itzkan, R. R. Dasari, and M. S. Feld, “Single molecule detection using surface-enhanced Raman scattering,” Phys. Rev. Lett. 78(9), 1667–1670 (1997).
[CrossRef]

Weber-Bargioni, A.

Z. Zhang, A. Weber-Bargioni, S. W. Wu, S. Dhuey, S. Cabrini, and P. J. Schuck, “Manipulating nanoscale light fields with the asymmetric bowtie nano-colorsorter,” Nano Lett. 9(12), 4505–4509 (2009).
[CrossRef] [PubMed]

Weiss, P. S.

Y. B. Zheng, Y. W. Yang, L. Jensen, L. Fang, B. K. Juluri, A. H. Flood, P. S. Weiss, J. F. Stoddart, and T. J. Huang, “Active molecular plasmonics: controlling plasmon resonances with molecular switches,” Nano Lett. 9(2), 819–825 (2009).
[CrossRef] [PubMed]

Willingham, B.

B. Willingham, D. Brandl, and P. Nordlander, “Plasmon hybridization in nanorod dimmers,” Appl. Phys. B 93(1), 209–216 (2008).
[CrossRef]

Wu, C. H.

J. A. Fan, C. H. Wu, K. Bao, J. Bao, R. Bardhan, N. J. Halas, V. N. Manoharan, P. Nordlander, G. Shvets, and F. Capasso, “Self-assembled plasmonic nanoparticle clusters,” Science 328(5982), 1135–1138 (2010).
[CrossRef] [PubMed]

Wu, S. W.

Z. Zhang, A. Weber-Bargioni, S. W. Wu, S. Dhuey, S. Cabrini, and P. J. Schuck, “Manipulating nanoscale light fields with the asymmetric bowtie nano-colorsorter,” Nano Lett. 9(12), 4505–4509 (2009).
[CrossRef] [PubMed]

Wurtz, G. A.

A. V. Kabashin, P. Evans, S. Pastkovsky, W. Hendren, G. A. Wurtz, R. Atkinson, R. Pollard, V. A. Podolskiy, and A. V. Zayats, “Plasmonic nanorod metamaterials for biosensing,” Nat. Mater. 8(11), 867–871 (2009).
[CrossRef] [PubMed]

Wustholz, K. L.

K. L. Wustholz, A. I. Henry, J. M. McMahon, R. G. Freeman, N. Valley, M. E. Piotti, M. J. Natan, G. C. Schatz, and R. P. Van Duyne, “Structure-activity relationships in gold nanoparticle dimers and trimers for surface-enhanced Raman spectroscopy,” J. Am. Chem. Soc. 132(31), 10903–10910 (2010).
[CrossRef] [PubMed]

Yang, Y. W.

Y. B. Zheng, Y. W. Yang, L. Jensen, L. Fang, B. K. Juluri, A. H. Flood, P. S. Weiss, J. F. Stoddart, and T. J. Huang, “Active molecular plasmonics: controlling plasmon resonances with molecular switches,” Nano Lett. 9(2), 819–825 (2009).
[CrossRef] [PubMed]

Yu, Z. F.

A. Kinkhabwala, Z. F. Yu, S. H. Fan, Y. Avlasevich, K. Mullen, and W. E. Moerner, “Large single-molecule fluorescence enhancements produced by a bowtie nanoantenna,” Nat. Photonics 3(11), 654–657 (2009).
[CrossRef]

Zayats, A. V.

A. V. Kabashin, P. Evans, S. Pastkovsky, W. Hendren, G. A. Wurtz, R. Atkinson, R. Pollard, V. A. Podolskiy, and A. V. Zayats, “Plasmonic nanorod metamaterials for biosensing,” Nat. Mater. 8(11), 867–871 (2009).
[CrossRef] [PubMed]

Zhang, Z.

Z. Zhang, A. Weber-Bargioni, S. W. Wu, S. Dhuey, S. Cabrini, and P. J. Schuck, “Manipulating nanoscale light fields with the asymmetric bowtie nano-colorsorter,” Nano Lett. 9(12), 4505–4509 (2009).
[CrossRef] [PubMed]

Zheng, Y. B.

Y. B. Zheng, Y. W. Yang, L. Jensen, L. Fang, B. K. Juluri, A. H. Flood, P. S. Weiss, J. F. Stoddart, and T. J. Huang, “Active molecular plasmonics: controlling plasmon resonances with molecular switches,” Nano Lett. 9(2), 819–825 (2009).
[CrossRef] [PubMed]

Adv. Mater.

S. A. Maier, M. L. Brongersma, P. G. Kik, S. Meltzer, A. A. G. Requicha, and H. A. Atwater, “Plasmonics - a route to nanoscale optical devices,” Adv. Mater. 13(19), 1501–1505 (2001).
[CrossRef]

Appl. Phys. B

B. Willingham, D. Brandl, and P. Nordlander, “Plasmon hybridization in nanorod dimmers,” Appl. Phys. B 93(1), 209–216 (2008).
[CrossRef]

Chem. Soc. Rev.

S. Lal, N. K. Grady, J. Kundu, C. S. Levin, J. B. Lassiter, and N. J. Halas, “Tailoring plasmonic substrates for surface enhanced spectroscopies,” Chem. Soc. Rev. 37(5), 898–911 (2008).
[CrossRef] [PubMed]

J. Am. Chem. Soc.

K. L. Wustholz, A. I. Henry, J. M. McMahon, R. G. Freeman, N. Valley, M. E. Piotti, M. J. Natan, G. C. Schatz, and R. P. Van Duyne, “Structure-activity relationships in gold nanoparticle dimers and trimers for surface-enhanced Raman spectroscopy,” J. Am. Chem. Soc. 132(31), 10903–10910 (2010).
[CrossRef] [PubMed]

Nano Lett.

P. K. Jain and M. A. El-Sayed, “Noble metal nanoparticle pairs: effect of medium for enhanced nanosensing,” Nano Lett. 8(12), 4347–4352 (2008).
[CrossRef]

M. Hentschel, M. Saliba, R. Vogelgesang, H. Giessen, A. P. Alivisatos, and N. Liu, “Transition from isolated to collective modes in plasmonic oligomers,” Nano Lett. 10(7), 2721–2726 (2010).
[CrossRef] [PubMed]

J. B. Lassiter, H. Sobhani, J. A. Fan, J. Kundu, F. Capasso, P. Nordlander, and N. J. Halas, “Fano resonances in plasmonic nanoclusters: geometrical and chemical tunability,” Nano Lett. 10(8), 3184–3189 (2010).
[CrossRef] [PubMed]

J. B. Lassiter, J. Aizpurua, L. I. Hernandez, D. W. Brandl, I. Romero, S. Lal, J. H. Hafner, P. Nordlander, and N. J. Halas, “Close encounters between two nanoshells,” Nano Lett. 8(4), 1212–1218 (2008).
[CrossRef] [PubMed]

E. M. Larsson, J. Alegret, M. Käll, and D. S. Sutherland, “Sensing characteristics of NIR localized surface plasmon resonances in gold nanorings for application as ultrasensitive biosensors,” Nano Lett. 7(5), 1256–1263 (2007).
[CrossRef] [PubMed]

Y. B. Zheng, Y. W. Yang, L. Jensen, L. Fang, B. K. Juluri, A. H. Flood, P. S. Weiss, J. F. Stoddart, and T. J. Huang, “Active molecular plasmonics: controlling plasmon resonances with molecular switches,” Nano Lett. 9(2), 819–825 (2009).
[CrossRef] [PubMed]

P. Nordlander, C. Oubre, E. Prodan, K. Li, and M. I. Stockman, “Plasmon hybridization in nanoparticle dimmers,” Nano Lett. 4(5), 899–903 (2004).
[CrossRef]

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(8), 1569–1574 (2005).
[CrossRef] [PubMed]

A. M. Funston, C. Novo, T. J. Davis, and P. Mulvaney, “Plasmon coupling of gold nanorods at short distances and in different geometries,” Nano Lett. 9(4), 1651–1658 (2009).
[CrossRef] [PubMed]

Z. Zhang, A. Weber-Bargioni, S. W. Wu, S. Dhuey, S. Cabrini, and P. J. Schuck, “Manipulating nanoscale light fields with the asymmetric bowtie nano-colorsorter,” Nano Lett. 9(12), 4505–4509 (2009).
[CrossRef] [PubMed]

Nanotechnology

V. K. Lin, S. L. Teo, R. Marty, A. Arbouet, Ch. Girard, E. Alarcon-Llado, S. H. Liu, M. Y. Han, S. Tripathy, and A. Mlayah, “Dual wavelength sensing based on interacting gold nanodisk trimers,” Nanotechnology 21(30), 305501 (2010).
[CrossRef] [PubMed]

Nat. Mater.

A. V. Kabashin, P. Evans, S. Pastkovsky, W. Hendren, G. A. Wurtz, R. Atkinson, R. Pollard, V. A. Podolskiy, and A. V. Zayats, “Plasmonic nanorod metamaterials for biosensing,” Nat. Mater. 8(11), 867–871 (2009).
[CrossRef] [PubMed]

Nat. Photonics

A. Kinkhabwala, Z. F. Yu, S. H. Fan, Y. Avlasevich, K. Mullen, and W. E. Moerner, “Large single-molecule fluorescence enhancements produced by a bowtie nanoantenna,” Nat. Photonics 3(11), 654–657 (2009).
[CrossRef]

Opt. Commun.

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(1-3), 137–141 (2003).
[CrossRef]

Opt. Express

Opt. Lett.

Phys. Rev. B

P. B. Johnson and R. W. Christy, “Optical constants of the nobel metals,” Phys. Rev. B 6(12), 4370–4379 (1972).
[CrossRef]

J. Aizpurua, G. W. Bryant, L. J. Richter, F. J. García de Abajo, B. K. Kelley, and T. Mallouk, “Optical properties of coupled metallic nanorods for field-enhanced spectroscopy,” Phys. Rev. B 71(23), 235420 (2005).
[CrossRef]

Phys. Rev. Lett.

F. J. García de Abajo and A. Howie, “Retarded field calculation of electron energy loss in inhomogeneous dielectrics”, Phys. Rev. Lett. 80, 5180–5183 (1998); “Retarded field calculation of electron energy loss in inhomogeneous dielectrics,” Phys. Rev. B 65, 115418 (2002).

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(5), 057401 (2003).
[CrossRef] [PubMed]

K. Kneipp, Y. Wang, H. Kneipp, L. T. Perelman, I. Itzkan, R. R. Dasari, and M. S. Feld, “Single molecule detection using surface-enhanced Raman scattering,” Phys. Rev. Lett. 78(9), 1667–1670 (1997).
[CrossRef]

Rep. Prog. Phys.

C. Girard, “Near fields in nanostructures,” Rep. Prog. Phys. 68(8), 1883–1933 (2005).
[CrossRef]

Science

J. A. Fan, C. H. Wu, K. Bao, J. Bao, R. Bardhan, N. J. Halas, V. N. Manoharan, P. Nordlander, G. Shvets, and F. Capasso, “Self-assembled plasmonic nanoparticle clusters,” Science 328(5982), 1135–1138 (2010).
[CrossRef] [PubMed]

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (6)

Fig. 1
Fig. 1

SEM image of gold nanorings NR120 and NR130, prepared by e-beam lithography and with outer diameter of 120 ± 3 nm (a) and 130 ± 3 nm (b), respectively. Both sets of rings have similar wall thickness of about 33 ± 3 nm. (c) The typical 3D AFM micrograph of the rings NR130 showing rounded shape of top ring wall. (d) An AFM section profile of the gold nanorings array showing the top rounded shape ring wall.

Fig. 2
Fig. 2

Measured (black) and calculated (blue) optical density spectra of nanorings NR130 (D out= 130 nm, D in= 70 nm) and NR120 (D out= 120 nm, D in= 60 nm). Spectra were simulated and measured in the transmission configuration. The optical density is obtained as log (1/T); where T is the transmission. In the inset is depicted a cross section of the ring wall. Flat (dotted lines) and two types of rounded ring wall profiles (dashed and solid lines) are considered in order to show the red-shift of the SPR wavelength when stressing the rounded shape of the ring wall.

Fig. 3
Fig. 3

(a) SEM images of ring dimers with variable gaps (0 to 30 nm) fabricated by EBL and lift-off process. (b) SEM image of nanoring trimers with a large periodicity (1000 nm pitch, isolated trimer with ring diameter 120 nm) and with nearly uniform spacing between top two rings in the trimer geometry. (c) SEM image of nanoring trimer array where the bottom ring outer diameter was kept at 120 nm with ≤15 nm average spacing between top two rings in touching and overlapping situations of ring walls. (d) SEM image of nanoring trimer array with ≤18 nm spacing between top two rings where the bottom ring outer diameter was kept at 130 nm. In the above cases, the ring trimers are arranged in a square lattice pattern with a pitch of 400 nm.

Fig. 4
Fig. 4

(a) Experimental tuning of the LSPR peaks by changing the bottom ring outer diameter in the nanoring trimers. The insets are schematic representations of the trimer geometry as well as a representative SEM image for each interacting trimer sample where the average spacing between top rings is around 15 nm. The separation between the trimers is about 400 nm. (b) The transmission (1–R) spectrum of nanoring trimers normalized to that of the spectrum of a 30 nm thick gold layer on quartz. The spectra obtained with a micro-FTIR set up reveals a clear dip around 3300 nm, which we tentatively attribute to the resonance related to the interaction between neighboring trimers.

Fig. 5
Fig. 5

Simulated extinction spectra and electric near-field intensity maps of the nanoring trimers. The computed spectra were averaged on several polarizations of the incident field in order to account for the measurements which were performed with unpolarized light. Calculations were performed for the case of bottom ring outer diameter of 120 and top two rings of a smaller diameter 110 nm. The gap between the top two rings is 15 nm. The nanorings have a rounded ring-wall shape. Three main situations are considered from our observations from SEM, where the bottom rings in trimers are separated (A), touching (B) or overlapping (C) with top two rings. The red dashed line in the left panel shows the extinction spectrum averaged over the three configurations. The electric near-field intensity maps are generated for the main SPR wavelengths and at distance Zobs = 70 nm from the nanoring trimer plane. The arrow indicates the polarization of the incident electromagnetic field. The examples of corresponding SEM images of such isolated trimers are shown in the inset.

Fig. 6
Fig. 6

(a) Transmission spectra of interacting ring trimers (bottom nanoring outer diameter of 120 nm within the trimer as shown in Fig. 4) when exposed to media of different refractive indices. The data show red-shifted LSPR with a higher refractive index medium and elucidate their potential in chemical sensing. (b) Wavelength shift of the near-infrared LSPR as a function of refractive index. The dotted line is a linear fit to the experimental data.

Metrics