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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 19, Iss. 4 — Feb. 14, 2011
  • pp: 3686–3693
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Gold nanoantenna resonance diagnostics via transversal particle plasmon luminescence

Matthias D. Wissert, Carola Moosmann, Konstantin S. Ilin, Michael Siegel, Uli Lemmer, and Hans-Jürgen Eisler  »View Author Affiliations


Optics Express, Vol. 19, Issue 4, pp. 3686-3693 (2011)
http://dx.doi.org/10.1364/OE.19.003686


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Abstract

We perform two-photon excitation confocal experiments on coupled gold nanoantennas and observe time-integrated luminescence spectra that match plasmonic mode emission in the far-field. We show that the transversal particle plasmon mode can be excited, using excitation light that is cross-polarized with respect to the gold luminescence signal and therefore oriented along the long axis of the dipole gold antenna. We provide evidence for losses in polarization information from the excitation channel to the luminescence response due to the nature of the energy and momentum transfer. Finally, we map out the two-photon induced luminescence intensity profile for a fixed excitation wavelength λ and varying antenna arm length L.

© 2011 Optical Society of America

1. Introduction

The properties of optical nanoantennas [1

1. D. Pohl, “Near field optics seen as an antenna problem,” In Near-Field Optics: Principles and Applications, M. Ohtsu and X. Zhu, editors, World Scientific, Singapore pp. 9–21 (2000).

5

5. L. Novotny, “Effective wavelength scaling for optical antennas,” Phys. Rev. Lett. 98, 266802 (2007). [CrossRef] [PubMed]

] are currently under extensive investigation from an experimental as well as a theoretical point-of-view. With electron beam lithography [6

6. P. Ghenuche, S. Cherukulappurath, T. Taminiau, N. van Hulst, and R. Quidant, “Spectroscopic mode mapping of resonant plasmon nanoantennas,” Phys. Rev. Lett. 101, 116805 (2008). [CrossRef] [PubMed]

10

10. M. Wissert, A. Schell, K. Ilin, M. Siegel, and H.-J. Eisler, “Nanoengineering and characterization of gold dipole-antennas with enhanced integrated scattering properties,” Nanotechnology 20, 425203 (2009). [CrossRef] [PubMed]

], possibly combined with focused ion beam milling [11

11. P. Mühlschlegel, H.-J. Eisler, O. Martin, B. Hecht, and D. Pohl, “Resonant optical antennas,” Science 308, 1607–1608 (2005). [CrossRef] [PubMed]

, 12

12. J. Huang, J. Kern, P. Geisler, P. Weinmann, M. Kamp, A. Forchel, P. Biagioni, and B. Hecht, “Mode imaging and selection in strongly coupled nanoantennas,” Nano Lett. 10, 2106–2110 (2010). [CrossRef]

], or chemical synthesis in addition to functionalization approaches [13

13. M. Schnell, A. Garcia-Etxarri, J. Alkorta, J. Aizpurua, and R. Hillenbrand, “Phase-resolved mapping of the near-field vector and polarization state in nanoscale antenna gaps,” Nano Lett. 10, 3524–3528 (2010). [CrossRef] [PubMed]

], such prototype antennas are accessible with high precision and reproducibility. The scattering spectrum of optical gold nanoantennas can be interpreted as an effect that is basically plasmonic in nature, with a tunable spectral response due to size, shape, material and the dielectric environment. Two-arm nanoantennas, two closely spaced single gold rods coupled in the near-field, include an additional feature. The nano-sized gap in between the arms enhances highly localized optical near-fields at wish. Two-arm optical antennas thus bridge the world of plasmonic optics and electrical engineering at the nanoscale with an account for ultra high frequencies [14

14. N. Engheta, “Circuits with light at nanoscales: Optical nanocircuits inspired by metamaterials,” Science 317, 1698–1702 (2007). [CrossRef] [PubMed]

].

As is commonly known, nanoantennas can exhibit both longitudinal and transversal modes. For gold antennas with small widths, such transversal modes are typically challenging to observe using scattering observations due to interband transitions which promote significant losses. If, however, the plasmonic gold luminescence is indeed not polarization conserving, then it should contain observable features cross-polarized to the excitation light, with an intensity corresponding to the density of states of the transversal modes. In the following, we present such luminescence spectra obtained from two-arm nanoantennas and uncoupled gold nanorods (termed single-arm antennas) under two-photon excitation conditions, where the excitation laser light is polarized along the long antenna axis and cross-polarized photoluminescence intensity data is observed. The claim that this cross-polarized light is indeed the transversal antenna mode is supported by numerical simulations. This observation is a powerful tool to map out the gold antenna resonant arm length L for a fixed laser excitation wavelength λ using the cross-polarized transversal mode emission intensity.

2. Experimental

Our gold nanoantenna fabrication protocol has been outlined previously [10

10. M. Wissert, A. Schell, K. Ilin, M. Siegel, and H.-J. Eisler, “Nanoengineering and characterization of gold dipole-antennas with enhanced integrated scattering properties,” Nanotechnology 20, 425203 (2009). [CrossRef] [PubMed]

]. In short, indium-tin-oxide (ITO, 30 nm thickness) was deposited onto a glass substrate. An electron-beam resist (PMMA, poly(methylmethacrylate)) was spun onto it, thereafter, electron-beam lithography was applied. After resist developement, gold with a final layer thickness of 30 nm was thermally evaporated. Following a lift-off process, optical two-arm antennas had been fabricated. They are 20 nm in width, have arms of varying length, and are coupled by a 20 nm gap. As reference structures, we also fabricated single-arm antennas of similar dimensions.

To obtain optical information, we used an epi-fluorescent microscope in the confocal mode with a sample piezo stage movable in (x,y,z)-dimensions (Fig. 1). The excitation laser (Coherent Mira Ti:Sa, 120 fs pulses, 76 MHz repetition rate, with center peak wavelength tuned to 810 nm) is first limited to wavelengths greater than 800 nm by a long-pass filter (Semrock Edge Basic BLP01-785R-25). The laser beam intensity can be adjusted by neutral density filters. Polarizers effectively set the state of the excitation polarization. The expanded laser beam is then sent into the microscope and directed via a 50:50 beam-splitter to the oil immersion objective (100x, NA 1.46). The diffraction limited laser spot interacts with the nanoantenna sample. The emitted light from the gold antenna is subsequently collected by the same objective. Only light with wavelength below 785 nm then passes through a short-pass filter (Semrock RazorEdge 785RU-25) in the detection path. A polarizer is introduced to only detect the transversal spectral response of the antennas. For detection, either an avalanche photo-diode detector (APD) (for intensity investigations) or a spectrometer (Acton 2500i) equipped with an Andor EMCCD camera, can be used, both accessible via a turnable mirror. The typical non-destructive laser power applied (as measured in front of the objective lens) was 10 μW for resonant two-arm antenna structures. For each pulse of approximately 500 fs width (corrected for broadening, e.g. due to beam-expanding lenses, at 76 MHz repetition rate), we thus have a laser fluence I of about 5102Jm2, assuming a focal area of π × 2002 nm2 and an objective lens transmission efficiency of 0.7 [21

21. Manufacturer data provided by Zeiss.

] at 810 nm wavelength. The laser excitation power required to excite single-arm antennas to obtain a similar SNR was around 10 times the power required for the corresponding two-arm structures.

Fig. 1 Measurement setup for the antenna TPL plasmon response. The inset shows an SEM image of an antenna of nominal arm length 45 nm and gap width 20 nm, the scale bar length is 100 nm.

3. Results and discussion

We present gold luminescence spectra of individual two-arm gold nanoantennas and additionally of single-arm antennas where the excitation laser light is polarized along the long axis of the nanostructure, but the cross-polarized gold luminescence is observed. Besides the fact that the transversal mode is observed, the measurements follow the scheme our group has presented earlier [20

20. M. Wissert, K. Ilin, M. Siegel, U. Lemmer, and H.-J. Eisler, “Coupled nanoantenna plasmon resonance spectra from two-photon laser excitation,” Nano Lett. 10, 4161–4165 (2010). [CrossRef] [PubMed]

]. The total integration time per spectrum was 30 s. The laser power was adjusted for each antenna length to yield a response with a favorable SNR avoiding the destruction of the nanostructures. Transversal luminescence spectra obtained from the two-arm and single-arm antennas can be found in Fig. 2. All response spectra have been normalized to unity to allow for an easy comparison of the spectral characteristics. If a two-arm antenna were measured with the same excitation power as a single-arm structure, the former would be about 10 to 100 times brighter. The two-photon nature of the process is confirmed by double-logarithmic excitation intensity - emission intensity plots which yield a slope of 2 (data not shown).

Fig. 2 Normalized TPL spectra for the transversal polarization component of the light emitted for (a) two-arm antenna and (b) single-arm antenna. Excitation was along the longitudinal axis only.

Looking at the TPL spectra depicted in Figs. 2(a) and 2(b), we observe a clear peak of the transversally polarized luminescence around 2.3 eV. The spectral shape appears to be fairly independent of the long axis length (although a small aspect-ratio dependency may be present) and also of any two-arm coupling. In addition, the signal is considerably less intense compared to the longitudinal signal which we have published previously [20

20. M. Wissert, K. Ilin, M. Siegel, U. Lemmer, and H.-J. Eisler, “Coupled nanoantenna plasmon resonance spectra from two-photon laser excitation,” Nano Lett. 10, 4161–4165 (2010). [CrossRef] [PubMed]

] (about two orders of magnitude). The peak position, which is significantly blue-shifted to the well-known longitudinal scattering resonances of such antenna structures [10

10. M. Wissert, A. Schell, K. Ilin, M. Siegel, and H.-J. Eisler, “Nanoengineering and characterization of gold dipole-antennas with enhanced integrated scattering properties,” Nanotechnology 20, 425203 (2009). [CrossRef] [PubMed]

], suggests that we in fact observe the transversal plasmon mode of the structures under investigation.

To support this claim, we performed numerical simulations using the FDTD-based software Lumerical [22

22. Lumerical FDTD Solution, http://www.lumerical.com/.

]. Those calculations are intended to simulate the scattering response, rather than the actual TPL experiment and hence to confirm that the measured TPL signal can be interpreted as the plasmonic scattering resonance. In these simulations, a plane wave with polarization perpendicular to the antenna length and parallel to the substrate surface was incident on gold nanoantennas. In agreement with experimental conditions, the antenna arm width was chosen to be 20 nm and the height 30 nm. The antenna is placed on a glass substrate (n=1.5) covered with a 30 nm ITO layer (complex, frequency dependent dielectric function [23

23. MIT, Photonic Bandgap Fibers & Devices Group, “Indium tin oxide (ITO),” http://mit-pbg.mit.edu/Pages/ITO.html.

]). The dielectric function of gold is taken from measurements by Johnson and Christy [24

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

]. All material parameters were fitted to a generalized multi-coefficient model supported in the FDTD simulation. The corners and edges of the antenna arms were rounded with a radius of 3 nm.

This circumvents singularities in the simulation, which would lead to unrealistically high field enhancements at theses corners. A simulation area of 8003 nm3 surrounded by 12 perfectly matched layers (PMLs) proved to be sufficient. The mesh cell size varied between 0.15 nm and 8 nm throughout the simulation area, and the plane wave was incident from inside the glass substrate. The scattered power was detected with a power monitor situated in the glass substrate 100 nm above the antenna. The former was then normalized by the incident intensity and is proportional to the power scattered backwards into the glass substrate. Figure 3 shows the relative scattering intensity of single-arm and two-arm antennas with arm lengths of 45 nm, 50 nm and 65 nm and a further single-arm antenna with arm length 150 nm. As can be seen, the peak position at 2.25 eV is in very good agreement with the peak position from the measured TPL emission spectra. Also, in accordance with measured results, there is hardly any shift in the peak position for different arm length and also not for coupled versus uncoupled antennas. With increased antenna volume, the scattering response simply increases. We can thus in fact assume that the transversal plasmon mode is observed.

Fig. 3 Numerical simulations of scattering spectra for single-arm and two-arm antennas with different arm lengths. The incident light was polarized along the transversal axis.

The energy transfer via excited electron states described by Dulkeith et al. [19

19. E. Dulkeith, T. Niedereichholz, T. Klar, J. Feldmann, G. von Plessen, D. Gittins, K. Mayya, and F. Caruso, “Plasmon emission in photoexcited gold nanoparticles,” Phys. Rev. B 70, 205424 (2004). [CrossRef]

] would specifically allow for the non-polarization-conserving effects we measure. Our experiment in conjunction with our simulation results thus gives further evidence that the model proposed there for single-photon excitation also holds true for TPL effects. It is interesting to see that the two-photon excitation technique in fact allows for a higher signal-to-noise-ratio (SNR) compared to scattering experiments, as now the transversal mode can easily be accessed due to efficient filtering of the excitation light.

It could be argued that the observed cross-polarized signal is in fact material-intrinsic, as a similar spectral response was observed for chemically synthesized gold nanorods under TPL exictation by e.g. Imura et al. [25

25. K. Imura, T. Nagahara, and H. Okamoto, “Near-field two-photon-induced photoluminescence from single gold nanorods and imaging of plasmon modes,” J. Phys. Chem. B 109, 13214–13220 (2005). [CrossRef]

] and Scolari et al. [26

26. M. Scolari, A. Mews, N. Fu, A. Myaltsin, T. Assmus, ’K. Balasubramanian, M. Burghard, and K. Kern, “Surface enhanced Raman scattering of carbon nanotubes decorated by individual fluorescent gold particles,” J. Phys. Chem. C 112, 391–396 (2008). [CrossRef]

]. We deem this unlikely for our case, however, as our structures are polycrystalline. Furthermore, we have not observed any L symmetry point luminescence contribution (which would appear in a similar spectral range around 2.3 eV) from non-resonant TPL on thin gold nanorods [27

27. M. Wissert, K. Ilin, M. Siegel, U. Lemmer, and H.-J. Eisler, “Highly localized non-linear optical white light response at nanorod ends from non-resonant excitation” Nanoscale 2, 1018–1020 (2010). [CrossRef] [PubMed]

]. It would be interesting to conduct comparative electron energy loss spectroscopy (EELS) measurements to possibly shed light on these apparent differences between chemically fabricated structures and antennas made using electron beam lithography.

Fig. 4 The normalized integrated luminescence photon counts from the transversal plasmon response for different antenna arm lengths under investigation. (a) gives the result for two-arm antennas, (b) depicts the intensity from single-arm antennas. The dashed line Gaussian fit is a guide to the eye.

4. Conclusions

We have verified with this detailed study that resonant gold dipole antennas both with and without gap under two-photon laser excitation along their long axis yield a cross-polarized luminescence response with a spectral peak that can be attributed to the transversal particle plasmon. We thus provide further evidence for the involvement of electronic states in the plasmon generation and subsequent photon emission process. In fact, this method is a largely tunable non-linear frequency conversion process - a matching antenna can be found for any desired excitation and emission wavelength regime, as long as one operates within the suitable wavelengths outside of absorption maxima for the material chosen. The resonant structure for a fixed excitation wavelength can be easily found using this TPL technique, exploiting the fact that transversal mode plasmon emission can be triggered by longitudinal excitation, and that the transversal modes fit the spectral detection window needed. This has extremely useful applications in setups where only laser excitation is available for the characterization of the nanostructures and can be used easily hand-in-hand with atomic force microscopy or tip-enhanced near-field techniques.

Acknowledgment

The authors thank H. Wermund for help with the gold evaporation process. M. W. and C. M. acknowledge generous support by the Karlsruhe School of Optics and Photonics (KSOP). K. I. and M. S. are partly supported by the Center for Functional Nanostructures (CFN). The corresponding author likes to acknowledge support through Deutsche Forschungsgemeinschaft (DFG) under the project DFG EI 442/3-1 and the DFG Heisenberg Excellence Fellowship DFG EI 442/2-2.

References and links

1.

D. Pohl, “Near field optics seen as an antenna problem,” In Near-Field Optics: Principles and Applications, M. Ohtsu and X. Zhu, editors, World Scientific, Singapore pp. 9–21 (2000).

2.

K. Crozier, A. Sundaramurthy, G. Kino, and C. Quate, “Optical antennas: Resonators for local field enhancement,” J. Appl. Phys. 94, 4632–4642 (2003). [CrossRef]

3.

J. Farahani, D. Pohl, H.-J. Eisler, and B. Hecht, “Single quantum dot coupled to a scanning optical antenna: A tunable superemitter,” Phys. Rev. Lett. 95, 017402 (2005). [CrossRef] [PubMed]

4.

S. Kühn, U. Hakanson, L. Rogobete, and V. Sandoghdar, “Enhancement of single-molecule fluorescence using a gold nanoparticle as an optical nanoantenna,” Phys. Rev. Lett. 97, 017402 (2006). [CrossRef] [PubMed]

5.

L. Novotny, “Effective wavelength scaling for optical antennas,” Phys. Rev. Lett. 98, 266802 (2007). [CrossRef] [PubMed]

6.

P. Ghenuche, S. Cherukulappurath, T. Taminiau, N. van Hulst, and R. Quidant, “Spectroscopic mode mapping of resonant plasmon nanoantennas,” Phys. Rev. Lett. 101, 116805 (2008). [CrossRef] [PubMed]

7.

A. Sundaramurthy, K. Crozier, G. Kino, D. Fromm, P. Schuck, and W. Moerner, “Field enhancement and gap-dependent resonance in a system of two opposing tip-to-tip au nanotriangles,” Phys. Rev. B 72, 165409 (2005). [CrossRef]

8.

P. Schuck, D. Fromm, A. Sundaramurthy, G. Kino, and W. Moerner, “Improving the mismatch between light and nanoscale objects with gold bowtie nanoantennas,” Phys. Rev. Lett. 94, 017402 (2005). [CrossRef] [PubMed]

9.

O. Muskens, V. Giannini, J. Sánchez, and J. Gómez-Rivas, “Optical scattering resonances of single and coupled dimer plasmonic nanoantennas,” Opt. Express 15, 17736–17746 (2007). [CrossRef] [PubMed]

10.

M. Wissert, A. Schell, K. Ilin, M. Siegel, and H.-J. Eisler, “Nanoengineering and characterization of gold dipole-antennas with enhanced integrated scattering properties,” Nanotechnology 20, 425203 (2009). [CrossRef] [PubMed]

11.

P. Mühlschlegel, H.-J. Eisler, O. Martin, B. Hecht, and D. Pohl, “Resonant optical antennas,” Science 308, 1607–1608 (2005). [CrossRef] [PubMed]

12.

J. Huang, J. Kern, P. Geisler, P. Weinmann, M. Kamp, A. Forchel, P. Biagioni, and B. Hecht, “Mode imaging and selection in strongly coupled nanoantennas,” Nano Lett. 10, 2106–2110 (2010). [CrossRef]

13.

M. Schnell, A. Garcia-Etxarri, J. Alkorta, J. Aizpurua, and R. Hillenbrand, “Phase-resolved mapping of the near-field vector and polarization state in nanoscale antenna gaps,” Nano Lett. 10, 3524–3528 (2010). [CrossRef] [PubMed]

14.

N. Engheta, “Circuits with light at nanoscales: Optical nanocircuits inspired by metamaterials,” Science 317, 1698–1702 (2007). [CrossRef] [PubMed]

15.

A. Mooradian, “Photoluminescence of metals,” Phys. Rev. Lett. 22, 185–187 (1969). [CrossRef]

16.

G. T. Boyd, Z. Yu, and Y. Shen, “Photoinduced luminescence from the noble metals and its enhancement on roughened surfaces,” Phys. Rev. B 33, 7923–7936 (1986). [CrossRef]

17.

M. Mohamed, V. Volkov, S. Link, and M. El-Sayed, “The ‘lightning’ gold nanorods: fluorescence enhancement of over a million compared to the gold metal,” Chem. Phys. Lett. 317, 517–523 (2000). [CrossRef]

18.

A. Bouhelier, R. Bachelot, G. Lerondel, S. Kostcheev, P. Royer, and G. Wiederrecht, “Surface plasmon characteristics of tunable photoluminescence in single gold nanorods,” Phys. Rev. Lett. 95, 267405 (2005). [CrossRef]

19.

E. Dulkeith, T. Niedereichholz, T. Klar, J. Feldmann, G. von Plessen, D. Gittins, K. Mayya, and F. Caruso, “Plasmon emission in photoexcited gold nanoparticles,” Phys. Rev. B 70, 205424 (2004). [CrossRef]

20.

M. Wissert, K. Ilin, M. Siegel, U. Lemmer, and H.-J. Eisler, “Coupled nanoantenna plasmon resonance spectra from two-photon laser excitation,” Nano Lett. 10, 4161–4165 (2010). [CrossRef] [PubMed]

21.

Manufacturer data provided by Zeiss.

22.

Lumerical FDTD Solution, http://www.lumerical.com/.

23.

MIT, Photonic Bandgap Fibers & Devices Group, “Indium tin oxide (ITO),” http://mit-pbg.mit.edu/Pages/ITO.html.

24.

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

25.

K. Imura, T. Nagahara, and H. Okamoto, “Near-field two-photon-induced photoluminescence from single gold nanorods and imaging of plasmon modes,” J. Phys. Chem. B 109, 13214–13220 (2005). [CrossRef]

26.

M. Scolari, A. Mews, N. Fu, A. Myaltsin, T. Assmus, ’K. Balasubramanian, M. Burghard, and K. Kern, “Surface enhanced Raman scattering of carbon nanotubes decorated by individual fluorescent gold particles,” J. Phys. Chem. C 112, 391–396 (2008). [CrossRef]

27.

M. Wissert, K. Ilin, M. Siegel, U. Lemmer, and H.-J. Eisler, “Highly localized non-linear optical white light response at nanorod ends from non-resonant excitation” Nanoscale 2, 1018–1020 (2010). [CrossRef] [PubMed]

28.

D.-S. Wang, F.-Y. Hsu, and C.-W. Lin, “Surface plasmon effects on two photon luminescence of gold nanorods,” Opt. Express 17, 11350–11359 (2009). [CrossRef] [PubMed]

29.

L. Novotny and B. Hecht, Principles of Nano-Optics, (Cambridge University Press, 2006).

OCIS Codes
(260.3910) Physical optics : Metal optics
(260.5740) Physical optics : Resonance
(250.5403) Optoelectronics : Plasmonics
(310.6628) Thin films : Subwavelength structures, nanostructures

ToC Category:
Optics at Surfaces

History
Original Manuscript: December 8, 2010
Revised Manuscript: January 20, 2011
Manuscript Accepted: January 20, 2011
Published: February 10, 2011

Virtual Issues
Vol. 6, Iss. 3 Virtual Journal for Biomedical Optics

Citation
Matthias D. Wissert, Carola Moosmann, Konstantin S. Ilin, Michael Siegel, Uli Lemmer, and Hans-Jürgen Eisler, "Gold nanoantenna resonance diagnostics via transversal particle plasmon luminescence," Opt. Express 19, 3686-3693 (2011)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-4-3686


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References

  1. D. Pohl, "Near field optics seen as an antenna problem," In Near-Field Optics: Principles and Applications, M. Ohtsu and X. Zhu, editors, World Scientific, Singapore pp. 9-21 (2000).
  2. K. Crozier, A. Sundaramurthy, G. Kino, and C. Quate, "Optical antennas: Resonators for local field enhancement," J. Appl. Phys. 94, 4632-4642 (2003). [CrossRef]
  3. J. Farahani, D. Pohl, H.-J. Eisler, and B. Hecht, "Single quantum dot coupled to a scanning optical antenna: A tunable superemitter," Phys. Rev. Lett. 95, 017402 (2005). [CrossRef] [PubMed]
  4. S. Kühn, U. Hakanson, L. Rogobete, and V. Sandoghdar, "Enhancement of single-molecule fluorescence using a gold nanoparticle as an optical nanoantenna," Phys. Rev. Lett. 97, 017402 (2006). [CrossRef] [PubMed]
  5. L. Novotny, "Effective wavelength scaling for optical antennas," Phys. Rev. Lett. 98, 266802 (2007). [CrossRef] [PubMed]
  6. P. Ghenuche, S. Cherukulappurath, T. Taminiau, N. van Hulst, and R. Quidant, "Spectroscopic mode mapping of resonant plasmon nanoantennas," Phys. Rev. Lett. 101, 116805 (2008). [CrossRef] [PubMed]
  7. A. Sundaramurthy, K. Crozier, G. Kino, D. Fromm, P. Schuck, and W. Moerner, "Field enhancement and gap dependent resonance in a system of two opposing tip-to-tip au nanotriangles," Phys. Rev. B 72, 165409 (2005). [CrossRef]
  8. P. Schuck, D. Fromm, A. Sundaramurthy, G. Kino, and W. Moerner, "Improving the mismatch between light and nanoscale objects with gold bowtie nanoantennas," Phys. Rev. Lett. 94, 017402 (2005). [CrossRef] [PubMed]
  9. O. Muskens, V. Giannini, J. S’anchez, and J. Gómez-Rivas, "Optical scattering resonances of single and coupled dimer plasmonic nanoantennas," Opt. Express 15, 17736-17746 (2007). [CrossRef] [PubMed]
  10. M. Wissert, A. Schell, K. Ilin, M. Siegel, and H.-J. Eisler, "Nanoengineering and characterization of gold dipole antennas with enhanced integrated scattering properties," Nanotechnology 20, 425203 (2009). [CrossRef] [PubMed]
  11. P. Mühlschlegel, H.-J. Eisler, O. Martin, B. Hecht, and D. Pohl, "Resonant optical antennas," Science 308, 1607-1608 (2005). [CrossRef] [PubMed]
  12. J. Huang, J. Kern, P. Geisler, P. Weinmann, M. Kamp, A. Forchel, P. Biagioni, and B. Hecht, "Mode imaging and selection in strongly coupled nanoantennas," Nano Lett. 10, 2106-2110 (2010). [CrossRef]
  13. M. Schnell, A. Garcia-Etxarri, J. Alkorta, J. Aizpurua, and R. Hillenbrand, "Phase-resolved mapping of the nearfield vector and polarization state in nanoscale antenna gaps," Nano Lett. 10, 3524-3528 (2010). [CrossRef] [PubMed]
  14. N. Engheta, "Circuits with light at nanoscales: Optical nanocircuits inspired by metamaterials," Science 317, 1698-1702 (2007). [CrossRef] [PubMed]
  15. A. Mooradian, "Photoluminescence of metals," Phys. Rev. Lett. 22, 185-187 (1969). [CrossRef]
  16. G. T. Boyd, Z. Yu, and Y. Shen, "Photoinduced luminescence from the noble metals and its enhancement on roughened surfaces," Phys. Rev. B 33, 7923-7936 (1986). [CrossRef]
  17. M. Mohamed, V. Volkov, S. Link, and M. El-Sayed, "The ‘lightning’ gold nanorods: fluorescence enhancement of over a million compared to the gold metal," Chem. Phys. Lett. 317, 517-523 (2000). [CrossRef]
  18. A. Bouhelier, R. Bachelot, G. Lerondel, S. Kostcheev, P. Royer, and G. Wiederrecht, "Surface plasmon characteristics of tunable photoluminescence in single gold nanorods," Phys. Rev. Lett. 95, 267405 (2005). [CrossRef]
  19. E. Dulkeith, T. Niedereichholz, T. Klar, J. Feldmann, G. von Plessen, D. Gittins, K. Mayya, and F. Caruso, "Plasmon emission in photoexcited gold nanoparticles," Phys. Rev. B 70, 205424 (2004). [CrossRef]
  20. M. Wissert, K. Ilin, M. Siegel, U. Lemmer, and H.-J. Eisler, "Coupled nanoantenna plasmon resonance spectra from two-photon laser excitation," Nano Lett. 10, 4161-4165 (2010). [CrossRef] [PubMed]
  21. Manufacturer data provided by Zeiss.
  22. Lumerical FDTD Solution, http://www.lumerical.com/.
  23. MIT, Photonic Bandgap Fibers & Devices Group, "Indium tin oxide (ITO)," http://mitpbg. mit.edu/Pages/ITO.html.
  24. P. Johnson, and R. Christy, "Optical constants of noble metals," Phys. Rev. B 6, 4370-4379 (1972). [CrossRef]
  25. K. Imura, T. Nagahara, and H. Okamoto, "Near-field two-photon-induced photoluminescence from single gold nanorods and imaging of plasmon modes," J. Phys. Chem. B 109, 13214-13220 (2005). [CrossRef]
  26. M. Scolari, A. Mews, N. Fu, A. Myaltsin, T. Assmus, K. Balasubramanian, M. Burghard, and K. Kern, "Surface enhanced Raman scattering of carbon nanotubes decorated by individual fluorescent gold particles," J. Phys. Chem. C 112, 391-396 (2008). [CrossRef]
  27. M. Wissert, K. Ilin, M. Siegel, U. Lemmer, and H.-J. Eisler, "Highly localized non-linear optical white light response at nanorod ends from non-resonant excitation," Nanoscale 2, 1018-1020 (2010). [CrossRef] [PubMed]
  28. D.-S. Wang, F.-Y. Hsu, and C.-W. Lin, "Surface plasmon effects on two photon luminescence of gold nanorods," Opt. Express 17, 11350-11359 (2009). [CrossRef] [PubMed]
  29. L. Novotny, and B. Hecht, Principles of Nano-Optics, (Cambridge University Press, 2006).

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