Abstract

Au/Ag nanoshuttles with sharp tips at both ends have been synthesized in glycine solution by chemically depositing silver on gold nanorods. Strong local field in the Au/Ag nanoshuttles enhanced by longitudinal surface plasmon resonance (LSPR) were investigated by theoretical calculations and experimental measurements. At the corresponding LSPR wavelengths, the extinction cross section and nonlinear refraction of the Au/Ag nanoshuttles are about 1.5 and 8.0 times of those of the original Au nanorods, respectively.

© 2008 Optical Society of America

1. Introduction

Surface plasmon resonance (SPR) excitation within the gold and silver nanostructures greatly enhances the local electric field [1-3]. This intense local field has been used to enhance the surface Raman scattering [4-7] and multiphoton luminescence [8-11], which have important applications in nanospectroscopy, biosensors and tissue imaging [12-15]. The frequency and intensity of SPR can be tuned by controlling the composition, size and shape of the nanostructures. It’s well known that the gold nanorods (Au NRs) and Ag nanobars have transverse and longitudinal SPRs (TSPR and LSPR), and their LSPR peaks can be easily tuned to the near-infrared (NIR) region for biological applications [13-15].

In general, the field enhancement can be significantly improved by the nanostructures with sharp corners [3,16,17], which motivated the studies on the synthesis and optical properties of metal nanocubes [18] and nanobipyramids [19,20]. Recently, the laser polarization dependent nonlinear field enhancement of single Ag nanobars and nanorice was also reported [5]. On the other hand, the composite metallic nanostructures with multiple elements are of significant interests from both nanotechnological and scientific points of view for improving catalytic activity and optical properties [21-23]. Especially, the bimetallic Au/Ag nanostructures have aroused much attention very recently due to their special optical properties for plasmon applications [24,25].

Here we report the synthesis of a novel Au/Ag nanostructure with sharp tips at both ends. Such nanostructure looks like the shuttle that pulls the thread of weft between the threads of warp, so we call it nanoshuttle [26]. The Au/Ag nanoshuttles have blue-shifted extinction peak and larger extinction cross section in comparison to the original Au NRs. The great field enhancement of the nanoshuttles was comparatively investigated by theoretical calculations of field distribution and experimental measurements on the nonlinear absorption and refraction. Though other “sharp” metal nanostructures also generate great localized field enhancement, these Au/Ag nanoshuttles can be easily adjusted the LSPR peak by changing the aspect ratio of the original Au NRs.

2. Synthesis and characterization

The original Au NRs were prepared through the seed-mediated growth method reported by El-Sayed et al. previously [27]. To synthesize Au/Ag nanoshuttles, 1 mL of Au NRs (2.9 pmol) were mixed with 1 mL of 0.2 M glycine acid and 30 µL of 2 M NaOH. After adding with 16 µL of 0.1 M AgNO3, the mixture were incubated at room temperature without stirring for 10 h. Finally, the solution was subjected to three centrifuge/wash cycles to stop the growth. We noted that previous studies also demonstrated that the silver atoms could be deposited onto the Au NRs to result in the formation of various Au/Ag core/shell nanostructures, such as I-shaped, corn-shaped, and dumbbell-shaped [28,29]. In our experiment, the Au/Ag nanoshuttles were efficiently shaped by controlling the concentration of Ag+ (0.78 mM), the pH (9-10) and the incubation time (around 10 h), and the sharpness of the tips could be controlled by just adjusting the incubation time. The transmittance electron microscopy (TEM) and high resolution TEM (HRTEM) images were measured with a JEOL 2010 HT and JEOL 2010 FET transmission electron microscope, respectively (operated at 200 kV). The extinction spectra were measured by using a Varian Cary 5000 UV-Vis-NIR spectrophotometer.

The TEM images in Fig. 1 clearly show that the Au/Ag nanoshuttles have sharp tips at both ends in comparison to the original Au NRs. The average height and width of the Au NRs measured from their TEM images including 110 particles (not shown) are 31±3 nm and 6.4±1 nm, respectively. The thickness of the silver shell of the Au/Ag nanoshuttle is about 1.6 nm. The HRTEM image shown in Fig. 1(c) reveals that the Ag atoms here prefer grow on the {111} facet of the Au NRs and consequently form sharp tips. In general, the competition of the overgrowth on different surface facets of the Au NRs results in highly anisotropic overgrowth pattern [29]. Relative to the {111} and {100} surfaces, the {110} facets of the Au NRs are less accessible for the overgrowth due to the stronger interactions with CTAB. This anisotropic overgrowth leads into the formation of the Au/Ag nanoshuttles.

 

Fig. 1. (a), (b) TEM images of Au NRs and Au/Ag nanoshuttles, respectively. (c) HRTEM image of one Au/Ag nanoshuttle.

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3. Extinction cross section

We calculated the extinction spectra of the averagely sized Au NRs and Au/Ag nanoshuttles under longitudinally polarized light by using discrete-dipole approximation (DDA) method (Fig. 2(a)). In our calculation, the dielectric functions of gold and silver were generated from Ref. 30 and the medium around the NRs was assumed to have a refractive index of 1.33 corresponding to that of water. Compared with the corresponding experimental extinction spectra shown in Fig. 2(b), the tendency of the extinction peak in the NIR region are precisely the same. In both the calculated and experimental spectra, the LSPR peak of the Au NRs is about 875 nm, and that of the Au/Ag nanoshuttles blue-shifts to about 755 nm, which is attributed to the silver coating [24]. Moreover, the extinction cross section at LSPR of the nanoshuttles increases about 50% comparing to that of the Au NRs, which indicates stronger local field enhancement in the nanoshuttles at the LSPR band. It should be noted that the experimental spectra show a broader LSPR band than calculated ones. The inhomogeneous broadening from the size and shape distribution is the main reason, while the possible contribution from additional scattering by boundaries should also be addressed [22].

 

Fig. 2. Calculated (a) and experimental (b) extinction spectra of Au NRs and Au/Ag nanoshuttles with insets giving TEM images, respectively.

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4. Field enhancement

We further performed finite-difference time-domain (FDTD) calculations [31] on an averagely sized Au NR and Au/Ag nanoshuttle to evaluate their local electric field enhancements. Fig. 3(a) and 3(b) show that the maximal field enhancement of the Au/Ag nanoshuttle is about 5.1 times that of the Au NR. It is obvious that the tips of the nanoshuttle are much sharper than the ends of the NR, thus the local electric field enhancement associated with the nanoshuttle is much larger than that associated with the NR, according to the lightning-rod effect [1]. Such tip effect from other nanostructures with sharp tips has been investigated previously [3,19]. To further investigate the tip effect, we have also performed the FDTD calculations on an Au nanoshuttle with the average size of the Au/Ag sample (data not shown), almost the same enhancement can be obtained. The results make the nanoshuttles highly attractive for the applications in designing substrates for surface-enhanced Raman scattering with the added advantage that the hot spots are completely open to the surrounding medium in this geometry. Moreover, because the LSPR wavelength of the Au/Ag nanoshuttles can be easily adjusted to the NIR region, where absorbance of light by biological tissues is at a minimum, these nanoshuttles can potentially be used in deep tissue applications.

 

Fig. 3. Resonant enhancement of local fields obtained from FDTD calculations of the averagely sized Au NR (a) and Au/Ag nanoshuttle (b) at a mesh size of 0.2 nm. (c) Electric field enhancement profiles along the longitudinal direction for (a) Au NR and (b) Au/Ag nanoshuttle. The origin is at their centers. They are excited at their respective LSP peak wavelengths and polarization parallel to the long axis.

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The electric field enhancements in the Au NRs and Au/Ag nanoshuttles can be indirectly measured through third-order susceptibility χ (3). Further, the real and imaginary parts of χ (3) are proportional to the nonlinear refraction (NLR) index γ and the nonlinear absorption (NLA) coefficient β with the relationships: Reχ (3)=2n ο 2 ε ο c γ, and Imχ (3)=n ο 2 ε ο c λ β/2π, where n ο is the linear refractive index, ε ο and c are the dielectric constant and the speed of light in the vacuum, respectively. The values of β and γ were measured by open- and closed-aperture Z-scans [32-35]. The laser pulses used in the Z-scan measurements were generated using a Ti: sapphire laser (Mira 900, Coherent) with a pulse width of 2.5 ps and a repetition rate of 76 MHz. The Au NRs and Au/Ag nanoshuttles were scanned around the waist of the focused Gaussian laser beam along Z axis and the irradiance on the samples varied as a function of Z position. The NLA coefficient β and the NLR index γ can be calculated from the normalized T OP and T CL by using the following relationships:

TOP=m=0(q0)m(1+z2z02)m(1+m)32
TCLTOP=1+4Δϕ0zz0((zz0)2+9)((zz0)2+1)

, where q ο=βI ο L eff and Δ ϕ0=γ kI ο L eff, I ο is the peak irradiance incident on the sample, L eff is the effective thickness of the sample, k=2π/λ, λ is the excitation wavelength, and z ο is the Rayleigh length of the Gaussian incident beam.

The measurements reveal that Reχ (3) >> Imχ (3) (shown in Fig. 4(a) and 4(b)) and the values of Reχ (3) reach the maxima at the excitation wavelength λ exc(Au)=860 nm and λ exc(Au/Ag)=760 nm (shown in Fig. 4(c)), which are very close to the corresponding LSPRs of the Au NRs and Au/Ag nanoshuttles, respectively. Fig. 4(a) and 4(b) also show the normalized open-aperture transmittance (T OP) and the closed-aperture transmittance normalized by the open-aperture transmittance (T CL/T OP) of the Au NRs and the Au/Ag nanoshuttles at the maximal χ (3). By using the above-mentioned two formulas, we get that γmax(Au)=-1.4×10-3 cm2/GW and χ (3) max(Au)=9.4×10-11 esu for Au NRs at λ exc=860 nm, and γ max(Au/Ag)=-1.1×10-2 cm2/GW and χ (3) max(Au/Ag)=-7.2×10-10 esu for Au/Ag nanoshuttles at λ exc=760 nm. Thus, χ (3) max(Au/Ag) is about 8 times that of χ (3) max(Au). These results indicate that the field enhancement factor of the Au/Ag nanoshuttles is about 2 times that of the Au NRs. It should be noted that the different nanoshuttles and NRs in the Z-scan measurements were excited at arbitrary polarization of the light, while the polarization of the excitation was parallel to their long axis in FDTD calculations. Such factor induced the discrepancy between the Z-scan measurements and the FDTD calculations on the field enhancement.

 

Fig. 4. Enhanced third-order optical nonlinearity of Au NRs and Au/Ag nanoshuttles: (a), (b) Open- and closed-aperture Z-scans of Au NRs and Au/Ag nanoshuttles when their NLR reaches the maxima around the corresponding LSPRs (λexc(Au)=860 nm, λ exc(Au/Ag)=760 nm). The scatter open circles are experimental data while the solid lines are the fitting curves by using the standard Z-scan theory. (c) The value of χ (3) vs the excitation wavelength.

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5. Conclusion

In conclusion, the synthesized Au/Ag nanoshuttles have sharp tips at the both ends and their linear absorption is blue-shifted and enhanced. By using the FDTD simulations and experimental measurements on the NLR and NLA, the Au/Ag nanoshuttles exhibit stronger local field enhancements than the original Au NRs. Such bimetallic nanostructures are expected to find use in plasmonic applications such as biosensors and tissue imaging.

Acknowledgments

This work was supported by the Natural Science Foundation of China (10534030) and the National Program on Key Science Research (2006CB921500, 2007CB935300).

References and links

1. M. B. Mohamed, V. Volkov, S. Link, and M. A. 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]  

2. M. T. Cheng, S. D. Liu, and Q. Q. Wang, “Modulating emission polarization of semiconductor quantum dots through surface plasmon of metal nanorod,” Appl. Phys. Lett. 92, 162107 (2008). [CrossRef]  

3. H. Wang, D. W. Brandl, F. Le, P. Nordlander, and N. J. Halas, “Nanorice: a hybrid plasmonic nanostructure,” Nano Lett. 6, 827–832 (2006). [CrossRef]   [PubMed]  

4. J. M. McLellan, A. Siekkinen, J. Chen, and Y. Xia, “Comparison of the surface-enhanced Raman scattering on sharp and truncated silver nanocubes,” Chem. Phys. Lett. 427, 122–126 (2006). [CrossRef]  

5. B. J. Wiley, Y. Chen, J. M. McLellan, Y. Xiong, Z. -Y. Li, D. Ginger, and Y. Xia, “Synthesis and optical properties of silver nanobars and nanorice,” Nano Lett. 7, 1032–1036 (2007). [CrossRef]   [PubMed]  

6. A. J. Haes, C. L. Haynes, A. D. McFarland, G. C. Schatz, R. P. Van Duyne, and S. L. Zou, “Plasmonic materials for surface-enhanced sensing and spectroscopy,” MRS Bull. 30, 368–375 (2005). [CrossRef]  

7. S. B. Chaney, S. Shanmukh, and R. A. Dluhy, “Aligned silver nanorod arrays produce high sensitivity SERS substrates,” Appl. Phys. Lett. 87, 031908 (2005). [CrossRef]  

8. J. Kupersztych and M. Raynaud, “Anomalous multiphoton photoelectric effect in ultrashort time scales,” Phys. Rev. Lett. 95, 147401 (2005). [CrossRef]   [PubMed]  

9. Q. Q. Wang, J. B. Han, D. L. Guo, S. Xiao, Y. B. Han, H. M. Gong, and X. W. Zou, “Highly efficient avalanche multiphoton luminescence from coupled Au nanowires in the visible region,” Nano Lett. 7, 723–728 (2007). [CrossRef]   [PubMed]  

10. C. Louis, S. Roux, G. Ledoux, L. Lemelle, P. Gillet, O. Tillement, and P. Perriat, “Gold nano-antennas for increasing luminescence,” Adv. Mater. 16, 2163–2166 (2004). [CrossRef]  

11. R. A. Farrer, F. L. Butterfield, V. W. Chen, and J. T. Fourkas, “Highly efficient multiphoton-absorption-induced luminescence from gold nanoparticles,” Nano Lett. 5, 1139–1142 (2005). [CrossRef]   [PubMed]  

12. P. Muhlschlegel, H. J. Eisler, O. J. F. Martin, B. Hecht, and D. W. Pohl, “Resonant optical antennas,” Science 308, 1607–1609 (2005). [CrossRef]   [PubMed]  

13. M. Hu, J. Chen, Z. -Y. Li, L. Au, G. V. Hartland, X. Li, M. Marquez, and Y. Xia, “Gold nanostructures: Engineering their plasmonic properties for biomedical applications,” Chem. Soc. Rev. 35, 1084–1094 (2006). [CrossRef]   [PubMed]  

14. M. Eghtedari, A. Oraevsky, J. A. Copland, N. A. Kotov, A. Conjusteau, and M. Motamedi, “High sensitivity of in vivo detection of gold nanorods using a laser optoacoustic imaging system,” Nano Lett. 7, 1914–1918 (2007). [CrossRef]   [PubMed]  

15. J. N. Anker, W. P. Hall, O. Lyandres, N. C. Shah, J. Zhao, and R. P. van Duyne, “Biosensing with plasmonic nanosensors,” Nat. Mater. 7, 442–453 (2008). [CrossRef]   [PubMed]  

16. F. Hao, C. L. Nehl, J. H. Hafner, and P. Nordlander, “Plasmon resonances of a gold nanostar,” Nano Lett. 7, 729–732 (2007). [CrossRef]   [PubMed]  

17. S. Kim, J. Jin, Y. J. Kim, I. Y. Park, Y. Kim, and S. W. Kim, “High-harmonic generation by resonant plasmon field enhancement,” Nature 453, 757–760 (2008). [CrossRef]   [PubMed]  

18. S. H. Im, Y. T. Lee, B. Wiley, and Y. N. Xia, “Large-scalesynthesis of silver nanocubes: the role of HCl in promotingcu be perfection and monodispersity,” Angew. Chem. Int. Ed. 44, 2154–2157 (2005). [CrossRef]  

19. X. Kou, W. Ni, C. -K. Tsung, K. Chan, H. -Q Lin, G. D. Stucky, and J. Wang, “Growth of gold bipyramids with improved yield and their curvature-directed oxidation,” Small 3, 2103–2113 (2007). [CrossRef]   [PubMed]  

20. B. J. Willey, Y. Xiong, Z. -Y. Li, Y. Yin, and Y. N. Xia, “Right bipyramids of silver: a new shape derived from single twinned seeds,” Nano Lett. 6, 765–768 (2006). [CrossRef]  

21. A. Sundaramurthy, P. J. Schuck, N. R. Conley, D. P. Fromm, G. S. Kino, and W. E. Moerner, “Toward nanometer-scale optical photolithography: utilizing the near-field of bowtie optical nanoantennas,” Nano Lett. 6, 355–360 (2006). [CrossRef]   [PubMed]  

22. M. Liu and P. Guyot-Sionnest, “Synthesis and optical characterization of Au/Ag core/shell nanorods,” J. Phys. Chem. B 108, 5882–5888 (2004). [CrossRef]  

23. O. M. Wilson, R. W. J. Scott, J. C. Garcia-Martinez, and R. M. Crooks, “Synthesis, characterization, and structure-selective extraction of 1-3nm diameter AuAg dendrimer-encapsulated bimetallic nanoparticles,” J. Am. Chem. Soc. 127, 1015–1024 (2005). [CrossRef]   [PubMed]  

24. J. Becker, I. Zins, A. Jakab, Y. Khalavka, O. Schubert, and C. Sönnichsen, “Plasmonic focusing reduces ensemble linewidth of silver-coated gold nanorods,” Nano Lett. 8, 1719–1723 (2008). [CrossRef]   [PubMed]  

25. S. D. Liu, M. T. Cheng, Z. J. Yang, and Q. Q. Wang, “Surface plasmon propagation in a pair of metal nanowires coupled to a nanosized optical emitter,” Opt. Lett. 33, 851–853 (2008). [CrossRef]   [PubMed]  

26. L. Y. Cheng, Y. Chen, and Q. S. Wu, “Morphology exchange and optical properties of monodispersed ZnS nanospheres and nanoshuttles,” Acta Chim. Sinica 17, 1851–1854 (2007).

27. B. Nikoobakht and M. A. El-Sayed, “Preparation and growth mechanism of gold nanorods(NRs) using seed-mediated growth method,” Chem. Mater. 15, 1957–1962 (2003). [CrossRef]  

28. Y. -F. Huang, Y. -W. Lin, and H. -T. Chang, “Growth of various Au-Ag nanocomposites from gold seeds in amino acid solutions,” Nanotechnology 17, 4885–4894 (2006). [CrossRef]  

29. C. -C. Huang, Z. Yang, and H. -T. Chang, “Synthesis of dumbbell-shaped Au-Ag Core-Shell nanorods by seed-mediated growth under alkaline conditions,” Langmuir 20, 6089–6092 (2004). [CrossRef]   [PubMed]  

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

31. A. Taflove and S. C. Hagness, Computational electrodynamics: The finite-difference time-domain method (Artech House, Boston, 2005).

32. M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurements of anisotropy of nonlinear refraction and absorption in crystals,” IEEE J. Quantum Electron. 26, 760–769 (1990). [CrossRef]  

33. Q. Q. Wang, J. B. Han, H. M. Gong, D. J. Chen, X. J. Zhao, J. Y. Feng, and J. J. Ren, “Linear and nonlinear optical properties of Ag nanowire polarizing glass,” Adv. Funct. Mater. 16, 2405–2408 (2006). [CrossRef]  

34. J. B. Han, D. J. Chen, S. Ding, H. J. Zhou, Y. B. Han, G. G. Xiong, and Q. Q. Wang, “Plasmon resonant absorption and third-order optical nonlinearity in Ag-Ti cosputtered composite films,” J. Appl. Phys. 99, 023526 (2006). [CrossRef]  

35. L. Gao, K. W. Yu, Z. Y. Li, and B. Hu, “Effective nonlinear optical properties of metal-dielectric composite media with shape distribution,” Phys. Rev. E 64, 036615 (2001). [CrossRef]  

References

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  1. M. B. Mohamed, V. Volkov, S. Link, and M. A. 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]
  2. M. T. Cheng, S. D. Liu, and Q. Q. Wang, "Modulating emission polarization of semiconductor quantum dots through surface plasmon of metal nanorod," Appl. Phys. Lett. 92, 162107 (2008).
    [CrossRef]
  3. H. Wang, D. W. Brandl, F. Le, P. Nordlander, and N. J. Halas, "Nanorice: a hybrid plasmonic nanostructure," Nano Lett. 6, 827-832 (2006).
    [CrossRef] [PubMed]
  4. J. M. McLellan, A. Siekkinen, J. Chen, and Y. Xia, "Comparison of the surface-enhanced Raman scattering on sharp and truncated silver nanocubes," Chem. Phys. Lett. 427, 122-126 (2006).
    [CrossRef]
  5. B. J. Wiley, Y. Chen, J. M. McLellan, Y. Xiong, Z. -Y. Li, D. Ginger, and Y. Xia, "Synthesis and optical properties of silver nanobars and nanorice," Nano Lett. 7, 1032-1036 (2007).
    [CrossRef] [PubMed]
  6. A. J. Haes, C. L. Haynes, A. D. McFarland, G. C. Schatz, R. P. Van Duyne, and S. L. Zou, "Plasmonic materials for surface-enhanced sensing and spectroscopy," MRS Bull. 30, 368-375 (2005).
    [CrossRef]
  7. S. B. Chaney, S. Shanmukh, and R. A. Dluhy, "Aligned silver nanorod arrays produce high sensitivity SERS substrates," Appl. Phys. Lett. 87, 031908 (2005).
    [CrossRef]
  8. J. Kupersztych and M. Raynaud, "Anomalous multiphoton photoelectric effect in ultrashort time scales," Phys. Rev. Lett. 95, 147401 (2005).
    [CrossRef] [PubMed]
  9. Q. Q. Wang, J. B. Han, D. L. Guo, S. Xiao, Y. B. Han, H. M. Gong, and X. W. Zou, "Highly efficient avalanche multiphoton luminescence from coupled Au nanowires in the visible region," Nano Lett. 7, 723-728 (2007).
    [CrossRef] [PubMed]
  10. C. Louis, S. Roux, G. Ledoux, L. Lemelle, P. Gillet, O. Tillement, and P. Perriat, "Gold nano-antennas for increasing luminescence," Adv. Mater. 16, 2163-2166 (2004).
    [CrossRef]
  11. R. A. Farrer, F. L. Butterfield, V. W. Chen, and J. T. Fourkas, "Highly efficient multiphoton-absorption-induced luminescence from gold nanoparticles," Nano Lett. 5, 1139-1142 (2005).
    [CrossRef] [PubMed]
  12. P. Muhlschlegel, H. J. Eisler, O. J. F. Martin, B. Hecht, and D. W. Pohl, "Resonant optical antennas," Science 308, 1607-1609 (2005).
    [CrossRef] [PubMed]
  13. M. Hu, J. Chen, Z. -Y. Li, L. Au, G. V. Hartland, X. Li, M. Marquez, and Y. Xia, "Gold nanostructures: Engineering their plasmonic properties for biomedical applications," Chem. Soc. Rev. 35, 1084-1094 (2006).
    [CrossRef] [PubMed]
  14. M. Eghtedari, A. Oraevsky, J. A. Copland, N. A. Kotov, A. Conjusteau, and M. Motamedi, "High sensitivity of in vivo detection of gold nanorods using a laser optoacoustic imaging system," Nano Lett. 7, 1914-1918 (2007).
    [CrossRef] [PubMed]
  15. J. N. Anker, W. P. Hall, O. Lyandres, N. C. Shah, J. Zhao, and R. P. van Duyne, "Biosensing with plasmonic nanosensors," Nat. Mater. 7, 442-453 (2008).
    [CrossRef] [PubMed]
  16. F. Hao, C. L. Nehl, J. H. Hafner, and P. Nordlander, "Plasmon resonances of a gold nanostar," Nano Lett. 7, 729-732 (2007).
    [CrossRef] [PubMed]
  17. S. Kim, J. Jin, Y. J. Kim, I. Y. Park, Y. Kim, and S. W. Kim, "High-harmonic generation by resonant plasmon field enhancement," Nature 453, 757-760 (2008).
    [CrossRef] [PubMed]
  18. S. H. Im, Y. T. Lee, B. Wiley, and Y. N. Xia, "Large-scalesynthesis of silver nanocubes: the role of HCl in promotingcu be perfection and monodispersity," Angew. Chem. Int. Ed. 44, 2154-2157 (2005).
    [CrossRef]
  19. X. Kou, W. Ni, C. -K. Tsung, K. Chan, H. -Q, Lin, G. D. Stucky, and J. Wang, "Growth of gold bipyramids with improved yield and their curvature-directed oxidation," Small 3, 2103-2113 (2007).
    [CrossRef] [PubMed]
  20. B. J. Willey, Y. Xiong, Z. -Y. Li, Y. Yin, and Y. N. Xia, "Right bipyramids of silver: a new shape derived from single twinned seeds," Nano Lett. 6, 765-768 (2006).
    [CrossRef]
  21. A. Sundaramurthy, P. J. Schuck, N. R. Conley, D. P. Fromm, G. S. Kino, and W. E. Moerner, "Toward nanometer-scale optical photolithography: utilizing the near-field of bowtie optical nanoantennas," Nano Lett. 6, 355-360 (2006).
    [CrossRef] [PubMed]
  22. M. Liu and P. Guyot-Sionnest, "Synthesis and optical characterization of Au/Ag core/shell nanorods," J. Phys. Chem. B 108, 5882-5888 (2004).
    [CrossRef]
  23. O. M. Wilson, R. W. J. Scott, J. C. Garcia-Martinez, and R. M. Crooks, "Synthesis, characterization, and structure-selective extraction of 1-3nm diameter AuAg dendrimer-encapsulated bimetallic nanoparticles," J. Am. Chem. Soc. 127, 1015-1024 (2005).
    [CrossRef] [PubMed]
  24. J. Becker, I. Zins, A. Jakab, Y. Khalavka, O. Schubert, and C. Sönnichsen, "Plasmonic focusing reduces ensemble linewidth of silver-coated gold nanorods," Nano Lett. 8, 1719-1723 (2008).
    [CrossRef] [PubMed]
  25. S. D. Liu, M. T. Cheng, Z. J. Yang, and Q. Q. Wang, "Surface plasmon propagation in a pair of metal nanowires coupled to a nanosized optical emitter," Opt. Lett. 33, 851-853 (2008).
    [CrossRef] [PubMed]
  26. L. Y. Cheng, Y. Chen, and Q. S. Wu, "Morphology exchange and optical properties of monodispersed ZnS nanospheres and nanoshuttles," Acta Chim. Sinica 17, 1851-1854 (2007).
  27. B. Nikoobakht and M. A. El-Sayed, "Preparation and growth mechanism of gold nanorods(NRs) using seed-mediated growth method," Chem. Mater. 15, 1957-1962 (2003).
    [CrossRef]
  28. Y. -F. Huang, Y. -W. Lin, and H. -T. Chang, "Growth of various Au-Ag nanocomposites from gold seeds in amino acid solutions," Nanotechnology 17, 4885-4894 (2006).
    [CrossRef]
  29. C. -C. Huang, Z. Yang, and H. -T. Chang, "Synthesis of dumbbell-shaped Au-Ag Core-Shell nanorods by seed-mediated growth under alkaline conditions," Langmuir 20, 6089-6092 (2004).
    [CrossRef] [PubMed]
  30. P. B. Johnson and R. W. Christy, "Optical constants of the noble metals," Phys. Rev. B 6, 4370-4379 (1972).
    [CrossRef]
  31. A. Taflove and S. C. Hagness, Computational electrodynamics: The finite-difference time-domain method (Artech House, Boston, 2005).
  32. M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, "Sensitive measurements of anisotropy of nonlinear refraction and absorption in crystals," IEEE J. Quantum Electron. 26, 760-769 (1990).
    [CrossRef]
  33. Q. Q. Wang, J. B. Han, H. M. Gong, D. J. Chen, X. J. Zhao, J. Y. Feng, and J. J. Ren, "Linear and nonlinear optical properties of Ag nanowire polarizing glass," Adv. Funct. Mater. 16, 2405-2408 (2006).
    [CrossRef]
  34. J. B. Han, D. J. Chen, S. Ding, H. J. Zhou, Y. B. Han, G. G. Xiong, and Q. Q. Wang, "Plasmon resonant absorption and third-order optical nonlinearity in Ag-Ti cosputtered composite films," J. Appl. Phys. 99, 023526 (2006).
    [CrossRef]
  35. L. Gao, K. W. Yu, Z. Y. Li, and B. Hu, "Effective nonlinear optical properties of metal-dielectric composite media with shape distribution," Phys. Rev. E 64, 036615 (2001).
    [CrossRef]

2008

M. T. Cheng, S. D. Liu, and Q. Q. Wang, "Modulating emission polarization of semiconductor quantum dots through surface plasmon of metal nanorod," Appl. Phys. Lett. 92, 162107 (2008).
[CrossRef]

J. N. Anker, W. P. Hall, O. Lyandres, N. C. Shah, J. Zhao, and R. P. van Duyne, "Biosensing with plasmonic nanosensors," Nat. Mater. 7, 442-453 (2008).
[CrossRef] [PubMed]

S. Kim, J. Jin, Y. J. Kim, I. Y. Park, Y. Kim, and S. W. Kim, "High-harmonic generation by resonant plasmon field enhancement," Nature 453, 757-760 (2008).
[CrossRef] [PubMed]

J. Becker, I. Zins, A. Jakab, Y. Khalavka, O. Schubert, and C. Sönnichsen, "Plasmonic focusing reduces ensemble linewidth of silver-coated gold nanorods," Nano Lett. 8, 1719-1723 (2008).
[CrossRef] [PubMed]

S. D. Liu, M. T. Cheng, Z. J. Yang, and Q. Q. Wang, "Surface plasmon propagation in a pair of metal nanowires coupled to a nanosized optical emitter," Opt. Lett. 33, 851-853 (2008).
[CrossRef] [PubMed]

2007

L. Y. Cheng, Y. Chen, and Q. S. Wu, "Morphology exchange and optical properties of monodispersed ZnS nanospheres and nanoshuttles," Acta Chim. Sinica 17, 1851-1854 (2007).

X. Kou, W. Ni, C. -K. Tsung, K. Chan, H. -Q, Lin, G. D. Stucky, and J. Wang, "Growth of gold bipyramids with improved yield and their curvature-directed oxidation," Small 3, 2103-2113 (2007).
[CrossRef] [PubMed]

M. Eghtedari, A. Oraevsky, J. A. Copland, N. A. Kotov, A. Conjusteau, and M. Motamedi, "High sensitivity of in vivo detection of gold nanorods using a laser optoacoustic imaging system," Nano Lett. 7, 1914-1918 (2007).
[CrossRef] [PubMed]

F. Hao, C. L. Nehl, J. H. Hafner, and P. Nordlander, "Plasmon resonances of a gold nanostar," Nano Lett. 7, 729-732 (2007).
[CrossRef] [PubMed]

Q. Q. Wang, J. B. Han, D. L. Guo, S. Xiao, Y. B. Han, H. M. Gong, and X. W. Zou, "Highly efficient avalanche multiphoton luminescence from coupled Au nanowires in the visible region," Nano Lett. 7, 723-728 (2007).
[CrossRef] [PubMed]

B. J. Wiley, Y. Chen, J. M. McLellan, Y. Xiong, Z. -Y. Li, D. Ginger, and Y. Xia, "Synthesis and optical properties of silver nanobars and nanorice," Nano Lett. 7, 1032-1036 (2007).
[CrossRef] [PubMed]

2006

H. Wang, D. W. Brandl, F. Le, P. Nordlander, and N. J. Halas, "Nanorice: a hybrid plasmonic nanostructure," Nano Lett. 6, 827-832 (2006).
[CrossRef] [PubMed]

J. M. McLellan, A. Siekkinen, J. Chen, and Y. Xia, "Comparison of the surface-enhanced Raman scattering on sharp and truncated silver nanocubes," Chem. Phys. Lett. 427, 122-126 (2006).
[CrossRef]

M. Hu, J. Chen, Z. -Y. Li, L. Au, G. V. Hartland, X. Li, M. Marquez, and Y. Xia, "Gold nanostructures: Engineering their plasmonic properties for biomedical applications," Chem. Soc. Rev. 35, 1084-1094 (2006).
[CrossRef] [PubMed]

Y. -F. Huang, Y. -W. Lin, and H. -T. Chang, "Growth of various Au-Ag nanocomposites from gold seeds in amino acid solutions," Nanotechnology 17, 4885-4894 (2006).
[CrossRef]

Q. Q. Wang, J. B. Han, H. M. Gong, D. J. Chen, X. J. Zhao, J. Y. Feng, and J. J. Ren, "Linear and nonlinear optical properties of Ag nanowire polarizing glass," Adv. Funct. Mater. 16, 2405-2408 (2006).
[CrossRef]

J. B. Han, D. J. Chen, S. Ding, H. J. Zhou, Y. B. Han, G. G. Xiong, and Q. Q. Wang, "Plasmon resonant absorption and third-order optical nonlinearity in Ag-Ti cosputtered composite films," J. Appl. Phys. 99, 023526 (2006).
[CrossRef]

B. J. Willey, Y. Xiong, Z. -Y. Li, Y. Yin, and Y. N. Xia, "Right bipyramids of silver: a new shape derived from single twinned seeds," Nano Lett. 6, 765-768 (2006).
[CrossRef]

A. Sundaramurthy, P. J. Schuck, N. R. Conley, D. P. Fromm, G. S. Kino, and W. E. Moerner, "Toward nanometer-scale optical photolithography: utilizing the near-field of bowtie optical nanoantennas," Nano Lett. 6, 355-360 (2006).
[CrossRef] [PubMed]

2005

O. M. Wilson, R. W. J. Scott, J. C. Garcia-Martinez, and R. M. Crooks, "Synthesis, characterization, and structure-selective extraction of 1-3nm diameter AuAg dendrimer-encapsulated bimetallic nanoparticles," J. Am. Chem. Soc. 127, 1015-1024 (2005).
[CrossRef] [PubMed]

R. A. Farrer, F. L. Butterfield, V. W. Chen, and J. T. Fourkas, "Highly efficient multiphoton-absorption-induced luminescence from gold nanoparticles," Nano Lett. 5, 1139-1142 (2005).
[CrossRef] [PubMed]

P. Muhlschlegel, H. J. Eisler, O. J. F. Martin, B. Hecht, and D. W. Pohl, "Resonant optical antennas," Science 308, 1607-1609 (2005).
[CrossRef] [PubMed]

S. H. Im, Y. T. Lee, B. Wiley, and Y. N. Xia, "Large-scalesynthesis of silver nanocubes: the role of HCl in promotingcu be perfection and monodispersity," Angew. Chem. Int. Ed. 44, 2154-2157 (2005).
[CrossRef]

A. J. Haes, C. L. Haynes, A. D. McFarland, G. C. Schatz, R. P. Van Duyne, and S. L. Zou, "Plasmonic materials for surface-enhanced sensing and spectroscopy," MRS Bull. 30, 368-375 (2005).
[CrossRef]

S. B. Chaney, S. Shanmukh, and R. A. Dluhy, "Aligned silver nanorod arrays produce high sensitivity SERS substrates," Appl. Phys. Lett. 87, 031908 (2005).
[CrossRef]

J. Kupersztych and M. Raynaud, "Anomalous multiphoton photoelectric effect in ultrashort time scales," Phys. Rev. Lett. 95, 147401 (2005).
[CrossRef] [PubMed]

2004

C. Louis, S. Roux, G. Ledoux, L. Lemelle, P. Gillet, O. Tillement, and P. Perriat, "Gold nano-antennas for increasing luminescence," Adv. Mater. 16, 2163-2166 (2004).
[CrossRef]

C. -C. Huang, Z. Yang, and H. -T. Chang, "Synthesis of dumbbell-shaped Au-Ag Core-Shell nanorods by seed-mediated growth under alkaline conditions," Langmuir 20, 6089-6092 (2004).
[CrossRef] [PubMed]

M. Liu and P. Guyot-Sionnest, "Synthesis and optical characterization of Au/Ag core/shell nanorods," J. Phys. Chem. B 108, 5882-5888 (2004).
[CrossRef]

2003

B. Nikoobakht and M. A. El-Sayed, "Preparation and growth mechanism of gold nanorods(NRs) using seed-mediated growth method," Chem. Mater. 15, 1957-1962 (2003).
[CrossRef]

2001

L. Gao, K. W. Yu, Z. Y. Li, and B. Hu, "Effective nonlinear optical properties of metal-dielectric composite media with shape distribution," Phys. Rev. E 64, 036615 (2001).
[CrossRef]

2000

M. B. Mohamed, V. Volkov, S. Link, and M. A. 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]

1990

M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, "Sensitive measurements of anisotropy of nonlinear refraction and absorption in crystals," IEEE J. Quantum Electron. 26, 760-769 (1990).
[CrossRef]

1972

P. B. Johnson and R. W. Christy, "Optical constants of the noble metals," Phys. Rev. B 6, 4370-4379 (1972).
[CrossRef]

Anker, J. N.

J. N. Anker, W. P. Hall, O. Lyandres, N. C. Shah, J. Zhao, and R. P. van Duyne, "Biosensing with plasmonic nanosensors," Nat. Mater. 7, 442-453 (2008).
[CrossRef] [PubMed]

Au, L.

M. Hu, J. Chen, Z. -Y. Li, L. Au, G. V. Hartland, X. Li, M. Marquez, and Y. Xia, "Gold nanostructures: Engineering their plasmonic properties for biomedical applications," Chem. Soc. Rev. 35, 1084-1094 (2006).
[CrossRef] [PubMed]

Becker, J.

J. Becker, I. Zins, A. Jakab, Y. Khalavka, O. Schubert, and C. Sönnichsen, "Plasmonic focusing reduces ensemble linewidth of silver-coated gold nanorods," Nano Lett. 8, 1719-1723 (2008).
[CrossRef] [PubMed]

Brandl, D. W.

H. Wang, D. W. Brandl, F. Le, P. Nordlander, and N. J. Halas, "Nanorice: a hybrid plasmonic nanostructure," Nano Lett. 6, 827-832 (2006).
[CrossRef] [PubMed]

Butterfield, F. L.

R. A. Farrer, F. L. Butterfield, V. W. Chen, and J. T. Fourkas, "Highly efficient multiphoton-absorption-induced luminescence from gold nanoparticles," Nano Lett. 5, 1139-1142 (2005).
[CrossRef] [PubMed]

Chan, K.

X. Kou, W. Ni, C. -K. Tsung, K. Chan, H. -Q, Lin, G. D. Stucky, and J. Wang, "Growth of gold bipyramids with improved yield and their curvature-directed oxidation," Small 3, 2103-2113 (2007).
[CrossRef] [PubMed]

Chaney, S. B.

S. B. Chaney, S. Shanmukh, and R. A. Dluhy, "Aligned silver nanorod arrays produce high sensitivity SERS substrates," Appl. Phys. Lett. 87, 031908 (2005).
[CrossRef]

Chang, H. -T.

Y. -F. Huang, Y. -W. Lin, and H. -T. Chang, "Growth of various Au-Ag nanocomposites from gold seeds in amino acid solutions," Nanotechnology 17, 4885-4894 (2006).
[CrossRef]

C. -C. Huang, Z. Yang, and H. -T. Chang, "Synthesis of dumbbell-shaped Au-Ag Core-Shell nanorods by seed-mediated growth under alkaline conditions," Langmuir 20, 6089-6092 (2004).
[CrossRef] [PubMed]

Chen, D. J.

Q. Q. Wang, J. B. Han, H. M. Gong, D. J. Chen, X. J. Zhao, J. Y. Feng, and J. J. Ren, "Linear and nonlinear optical properties of Ag nanowire polarizing glass," Adv. Funct. Mater. 16, 2405-2408 (2006).
[CrossRef]

J. B. Han, D. J. Chen, S. Ding, H. J. Zhou, Y. B. Han, G. G. Xiong, and Q. Q. Wang, "Plasmon resonant absorption and third-order optical nonlinearity in Ag-Ti cosputtered composite films," J. Appl. Phys. 99, 023526 (2006).
[CrossRef]

Chen, J.

J. M. McLellan, A. Siekkinen, J. Chen, and Y. Xia, "Comparison of the surface-enhanced Raman scattering on sharp and truncated silver nanocubes," Chem. Phys. Lett. 427, 122-126 (2006).
[CrossRef]

M. Hu, J. Chen, Z. -Y. Li, L. Au, G. V. Hartland, X. Li, M. Marquez, and Y. Xia, "Gold nanostructures: Engineering their plasmonic properties for biomedical applications," Chem. Soc. Rev. 35, 1084-1094 (2006).
[CrossRef] [PubMed]

Chen, V. W.

R. A. Farrer, F. L. Butterfield, V. W. Chen, and J. T. Fourkas, "Highly efficient multiphoton-absorption-induced luminescence from gold nanoparticles," Nano Lett. 5, 1139-1142 (2005).
[CrossRef] [PubMed]

Chen, Y.

B. J. Wiley, Y. Chen, J. M. McLellan, Y. Xiong, Z. -Y. Li, D. Ginger, and Y. Xia, "Synthesis and optical properties of silver nanobars and nanorice," Nano Lett. 7, 1032-1036 (2007).
[CrossRef] [PubMed]

L. Y. Cheng, Y. Chen, and Q. S. Wu, "Morphology exchange and optical properties of monodispersed ZnS nanospheres and nanoshuttles," Acta Chim. Sinica 17, 1851-1854 (2007).

Cheng, L. Y.

L. Y. Cheng, Y. Chen, and Q. S. Wu, "Morphology exchange and optical properties of monodispersed ZnS nanospheres and nanoshuttles," Acta Chim. Sinica 17, 1851-1854 (2007).

Cheng, M. T.

S. D. Liu, M. T. Cheng, Z. J. Yang, and Q. Q. Wang, "Surface plasmon propagation in a pair of metal nanowires coupled to a nanosized optical emitter," Opt. Lett. 33, 851-853 (2008).
[CrossRef] [PubMed]

M. T. Cheng, S. D. Liu, and Q. Q. Wang, "Modulating emission polarization of semiconductor quantum dots through surface plasmon of metal nanorod," Appl. Phys. Lett. 92, 162107 (2008).
[CrossRef]

Christy, R. W.

P. B. Johnson and R. W. Christy, "Optical constants of the noble metals," Phys. Rev. B 6, 4370-4379 (1972).
[CrossRef]

Conjusteau, A.

M. Eghtedari, A. Oraevsky, J. A. Copland, N. A. Kotov, A. Conjusteau, and M. Motamedi, "High sensitivity of in vivo detection of gold nanorods using a laser optoacoustic imaging system," Nano Lett. 7, 1914-1918 (2007).
[CrossRef] [PubMed]

Conley, N. R.

A. Sundaramurthy, P. J. Schuck, N. R. Conley, D. P. Fromm, G. S. Kino, and W. E. Moerner, "Toward nanometer-scale optical photolithography: utilizing the near-field of bowtie optical nanoantennas," Nano Lett. 6, 355-360 (2006).
[CrossRef] [PubMed]

Copland, J. A.

M. Eghtedari, A. Oraevsky, J. A. Copland, N. A. Kotov, A. Conjusteau, and M. Motamedi, "High sensitivity of in vivo detection of gold nanorods using a laser optoacoustic imaging system," Nano Lett. 7, 1914-1918 (2007).
[CrossRef] [PubMed]

Crooks, R. M.

O. M. Wilson, R. W. J. Scott, J. C. Garcia-Martinez, and R. M. Crooks, "Synthesis, characterization, and structure-selective extraction of 1-3nm diameter AuAg dendrimer-encapsulated bimetallic nanoparticles," J. Am. Chem. Soc. 127, 1015-1024 (2005).
[CrossRef] [PubMed]

Ding, S.

J. B. Han, D. J. Chen, S. Ding, H. J. Zhou, Y. B. Han, G. G. Xiong, and Q. Q. Wang, "Plasmon resonant absorption and third-order optical nonlinearity in Ag-Ti cosputtered composite films," J. Appl. Phys. 99, 023526 (2006).
[CrossRef]

Dluhy, R. A.

S. B. Chaney, S. Shanmukh, and R. A. Dluhy, "Aligned silver nanorod arrays produce high sensitivity SERS substrates," Appl. Phys. Lett. 87, 031908 (2005).
[CrossRef]

Eghtedari, M.

M. Eghtedari, A. Oraevsky, J. A. Copland, N. A. Kotov, A. Conjusteau, and M. Motamedi, "High sensitivity of in vivo detection of gold nanorods using a laser optoacoustic imaging system," Nano Lett. 7, 1914-1918 (2007).
[CrossRef] [PubMed]

Eisler, H. J.

P. Muhlschlegel, H. J. Eisler, O. J. F. Martin, B. Hecht, and D. W. Pohl, "Resonant optical antennas," Science 308, 1607-1609 (2005).
[CrossRef] [PubMed]

El-Sayed, M. A.

B. Nikoobakht and M. A. El-Sayed, "Preparation and growth mechanism of gold nanorods(NRs) using seed-mediated growth method," Chem. Mater. 15, 1957-1962 (2003).
[CrossRef]

M. B. Mohamed, V. Volkov, S. Link, and M. A. 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]

Farrer, R. A.

R. A. Farrer, F. L. Butterfield, V. W. Chen, and J. T. Fourkas, "Highly efficient multiphoton-absorption-induced luminescence from gold nanoparticles," Nano Lett. 5, 1139-1142 (2005).
[CrossRef] [PubMed]

Feng, J. Y.

Q. Q. Wang, J. B. Han, H. M. Gong, D. J. Chen, X. J. Zhao, J. Y. Feng, and J. J. Ren, "Linear and nonlinear optical properties of Ag nanowire polarizing glass," Adv. Funct. Mater. 16, 2405-2408 (2006).
[CrossRef]

Fourkas, J. T.

R. A. Farrer, F. L. Butterfield, V. W. Chen, and J. T. Fourkas, "Highly efficient multiphoton-absorption-induced luminescence from gold nanoparticles," Nano Lett. 5, 1139-1142 (2005).
[CrossRef] [PubMed]

Fromm, D. P.

A. Sundaramurthy, P. J. Schuck, N. R. Conley, D. P. Fromm, G. S. Kino, and W. E. Moerner, "Toward nanometer-scale optical photolithography: utilizing the near-field of bowtie optical nanoantennas," Nano Lett. 6, 355-360 (2006).
[CrossRef] [PubMed]

Gao, L.

L. Gao, K. W. Yu, Z. Y. Li, and B. Hu, "Effective nonlinear optical properties of metal-dielectric composite media with shape distribution," Phys. Rev. E 64, 036615 (2001).
[CrossRef]

Garcia-Martinez, J. C.

O. M. Wilson, R. W. J. Scott, J. C. Garcia-Martinez, and R. M. Crooks, "Synthesis, characterization, and structure-selective extraction of 1-3nm diameter AuAg dendrimer-encapsulated bimetallic nanoparticles," J. Am. Chem. Soc. 127, 1015-1024 (2005).
[CrossRef] [PubMed]

Gillet, P.

C. Louis, S. Roux, G. Ledoux, L. Lemelle, P. Gillet, O. Tillement, and P. Perriat, "Gold nano-antennas for increasing luminescence," Adv. Mater. 16, 2163-2166 (2004).
[CrossRef]

Ginger, D.

B. J. Wiley, Y. Chen, J. M. McLellan, Y. Xiong, Z. -Y. Li, D. Ginger, and Y. Xia, "Synthesis and optical properties of silver nanobars and nanorice," Nano Lett. 7, 1032-1036 (2007).
[CrossRef] [PubMed]

Gong, H. M.

Q. Q. Wang, J. B. Han, D. L. Guo, S. Xiao, Y. B. Han, H. M. Gong, and X. W. Zou, "Highly efficient avalanche multiphoton luminescence from coupled Au nanowires in the visible region," Nano Lett. 7, 723-728 (2007).
[CrossRef] [PubMed]

Q. Q. Wang, J. B. Han, H. M. Gong, D. J. Chen, X. J. Zhao, J. Y. Feng, and J. J. Ren, "Linear and nonlinear optical properties of Ag nanowire polarizing glass," Adv. Funct. Mater. 16, 2405-2408 (2006).
[CrossRef]

Guo, D. L.

Q. Q. Wang, J. B. Han, D. L. Guo, S. Xiao, Y. B. Han, H. M. Gong, and X. W. Zou, "Highly efficient avalanche multiphoton luminescence from coupled Au nanowires in the visible region," Nano Lett. 7, 723-728 (2007).
[CrossRef] [PubMed]

Guyot-Sionnest, P.

M. Liu and P. Guyot-Sionnest, "Synthesis and optical characterization of Au/Ag core/shell nanorods," J. Phys. Chem. B 108, 5882-5888 (2004).
[CrossRef]

Haes, A. J.

A. J. Haes, C. L. Haynes, A. D. McFarland, G. C. Schatz, R. P. Van Duyne, and S. L. Zou, "Plasmonic materials for surface-enhanced sensing and spectroscopy," MRS Bull. 30, 368-375 (2005).
[CrossRef]

Hafner, J. H.

F. Hao, C. L. Nehl, J. H. Hafner, and P. Nordlander, "Plasmon resonances of a gold nanostar," Nano Lett. 7, 729-732 (2007).
[CrossRef] [PubMed]

Hagan, D. J.

M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, "Sensitive measurements of anisotropy of nonlinear refraction and absorption in crystals," IEEE J. Quantum Electron. 26, 760-769 (1990).
[CrossRef]

Halas, N. J.

H. Wang, D. W. Brandl, F. Le, P. Nordlander, and N. J. Halas, "Nanorice: a hybrid plasmonic nanostructure," Nano Lett. 6, 827-832 (2006).
[CrossRef] [PubMed]

Hall, W. P.

J. N. Anker, W. P. Hall, O. Lyandres, N. C. Shah, J. Zhao, and R. P. van Duyne, "Biosensing with plasmonic nanosensors," Nat. Mater. 7, 442-453 (2008).
[CrossRef] [PubMed]

Han, J. B.

Q. Q. Wang, J. B. Han, D. L. Guo, S. Xiao, Y. B. Han, H. M. Gong, and X. W. Zou, "Highly efficient avalanche multiphoton luminescence from coupled Au nanowires in the visible region," Nano Lett. 7, 723-728 (2007).
[CrossRef] [PubMed]

Q. Q. Wang, J. B. Han, H. M. Gong, D. J. Chen, X. J. Zhao, J. Y. Feng, and J. J. Ren, "Linear and nonlinear optical properties of Ag nanowire polarizing glass," Adv. Funct. Mater. 16, 2405-2408 (2006).
[CrossRef]

J. B. Han, D. J. Chen, S. Ding, H. J. Zhou, Y. B. Han, G. G. Xiong, and Q. Q. Wang, "Plasmon resonant absorption and third-order optical nonlinearity in Ag-Ti cosputtered composite films," J. Appl. Phys. 99, 023526 (2006).
[CrossRef]

Han, Y. B.

Q. Q. Wang, J. B. Han, D. L. Guo, S. Xiao, Y. B. Han, H. M. Gong, and X. W. Zou, "Highly efficient avalanche multiphoton luminescence from coupled Au nanowires in the visible region," Nano Lett. 7, 723-728 (2007).
[CrossRef] [PubMed]

J. B. Han, D. J. Chen, S. Ding, H. J. Zhou, Y. B. Han, G. G. Xiong, and Q. Q. Wang, "Plasmon resonant absorption and third-order optical nonlinearity in Ag-Ti cosputtered composite films," J. Appl. Phys. 99, 023526 (2006).
[CrossRef]

Hao, F.

F. Hao, C. L. Nehl, J. H. Hafner, and P. Nordlander, "Plasmon resonances of a gold nanostar," Nano Lett. 7, 729-732 (2007).
[CrossRef] [PubMed]

Hartland, G. V.

M. Hu, J. Chen, Z. -Y. Li, L. Au, G. V. Hartland, X. Li, M. Marquez, and Y. Xia, "Gold nanostructures: Engineering their plasmonic properties for biomedical applications," Chem. Soc. Rev. 35, 1084-1094 (2006).
[CrossRef] [PubMed]

Haynes, C. L.

A. J. Haes, C. L. Haynes, A. D. McFarland, G. C. Schatz, R. P. Van Duyne, and S. L. Zou, "Plasmonic materials for surface-enhanced sensing and spectroscopy," MRS Bull. 30, 368-375 (2005).
[CrossRef]

Hecht, B.

P. Muhlschlegel, H. J. Eisler, O. J. F. Martin, B. Hecht, and D. W. Pohl, "Resonant optical antennas," Science 308, 1607-1609 (2005).
[CrossRef] [PubMed]

Hu, B.

L. Gao, K. W. Yu, Z. Y. Li, and B. Hu, "Effective nonlinear optical properties of metal-dielectric composite media with shape distribution," Phys. Rev. E 64, 036615 (2001).
[CrossRef]

Hu, M.

M. Hu, J. Chen, Z. -Y. Li, L. Au, G. V. Hartland, X. Li, M. Marquez, and Y. Xia, "Gold nanostructures: Engineering their plasmonic properties for biomedical applications," Chem. Soc. Rev. 35, 1084-1094 (2006).
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C. -C. Huang, Z. Yang, and H. -T. Chang, "Synthesis of dumbbell-shaped Au-Ag Core-Shell nanorods by seed-mediated growth under alkaline conditions," Langmuir 20, 6089-6092 (2004).
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Huang, Y. -F.

Y. -F. Huang, Y. -W. Lin, and H. -T. Chang, "Growth of various Au-Ag nanocomposites from gold seeds in amino acid solutions," Nanotechnology 17, 4885-4894 (2006).
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S. H. Im, Y. T. Lee, B. Wiley, and Y. N. Xia, "Large-scalesynthesis of silver nanocubes: the role of HCl in promotingcu be perfection and monodispersity," Angew. Chem. Int. Ed. 44, 2154-2157 (2005).
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Jakab, A.

J. Becker, I. Zins, A. Jakab, Y. Khalavka, O. Schubert, and C. Sönnichsen, "Plasmonic focusing reduces ensemble linewidth of silver-coated gold nanorods," Nano Lett. 8, 1719-1723 (2008).
[CrossRef] [PubMed]

Jin, J.

S. Kim, J. Jin, Y. J. Kim, I. Y. Park, Y. Kim, and S. W. Kim, "High-harmonic generation by resonant plasmon field enhancement," Nature 453, 757-760 (2008).
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P. B. Johnson and R. W. Christy, "Optical constants of the noble metals," Phys. Rev. B 6, 4370-4379 (1972).
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Khalavka, Y.

J. Becker, I. Zins, A. Jakab, Y. Khalavka, O. Schubert, and C. Sönnichsen, "Plasmonic focusing reduces ensemble linewidth of silver-coated gold nanorods," Nano Lett. 8, 1719-1723 (2008).
[CrossRef] [PubMed]

Kim, S.

S. Kim, J. Jin, Y. J. Kim, I. Y. Park, Y. Kim, and S. W. Kim, "High-harmonic generation by resonant plasmon field enhancement," Nature 453, 757-760 (2008).
[CrossRef] [PubMed]

Kim, S. W.

S. Kim, J. Jin, Y. J. Kim, I. Y. Park, Y. Kim, and S. W. Kim, "High-harmonic generation by resonant plasmon field enhancement," Nature 453, 757-760 (2008).
[CrossRef] [PubMed]

Kim, Y.

S. Kim, J. Jin, Y. J. Kim, I. Y. Park, Y. Kim, and S. W. Kim, "High-harmonic generation by resonant plasmon field enhancement," Nature 453, 757-760 (2008).
[CrossRef] [PubMed]

Kim, Y. J.

S. Kim, J. Jin, Y. J. Kim, I. Y. Park, Y. Kim, and S. W. Kim, "High-harmonic generation by resonant plasmon field enhancement," Nature 453, 757-760 (2008).
[CrossRef] [PubMed]

Kino, G. S.

A. Sundaramurthy, P. J. Schuck, N. R. Conley, D. P. Fromm, G. S. Kino, and W. E. Moerner, "Toward nanometer-scale optical photolithography: utilizing the near-field of bowtie optical nanoantennas," Nano Lett. 6, 355-360 (2006).
[CrossRef] [PubMed]

Kotov, N. A.

M. Eghtedari, A. Oraevsky, J. A. Copland, N. A. Kotov, A. Conjusteau, and M. Motamedi, "High sensitivity of in vivo detection of gold nanorods using a laser optoacoustic imaging system," Nano Lett. 7, 1914-1918 (2007).
[CrossRef] [PubMed]

Kou, X.

X. Kou, W. Ni, C. -K. Tsung, K. Chan, H. -Q, Lin, G. D. Stucky, and J. Wang, "Growth of gold bipyramids with improved yield and their curvature-directed oxidation," Small 3, 2103-2113 (2007).
[CrossRef] [PubMed]

Kupersztych, J.

J. Kupersztych and M. Raynaud, "Anomalous multiphoton photoelectric effect in ultrashort time scales," Phys. Rev. Lett. 95, 147401 (2005).
[CrossRef] [PubMed]

Le, F.

H. Wang, D. W. Brandl, F. Le, P. Nordlander, and N. J. Halas, "Nanorice: a hybrid plasmonic nanostructure," Nano Lett. 6, 827-832 (2006).
[CrossRef] [PubMed]

Ledoux, G.

C. Louis, S. Roux, G. Ledoux, L. Lemelle, P. Gillet, O. Tillement, and P. Perriat, "Gold nano-antennas for increasing luminescence," Adv. Mater. 16, 2163-2166 (2004).
[CrossRef]

Lee, Y. T.

S. H. Im, Y. T. Lee, B. Wiley, and Y. N. Xia, "Large-scalesynthesis of silver nanocubes: the role of HCl in promotingcu be perfection and monodispersity," Angew. Chem. Int. Ed. 44, 2154-2157 (2005).
[CrossRef]

Lemelle, L.

C. Louis, S. Roux, G. Ledoux, L. Lemelle, P. Gillet, O. Tillement, and P. Perriat, "Gold nano-antennas for increasing luminescence," Adv. Mater. 16, 2163-2166 (2004).
[CrossRef]

Li, X.

M. Hu, J. Chen, Z. -Y. Li, L. Au, G. V. Hartland, X. Li, M. Marquez, and Y. Xia, "Gold nanostructures: Engineering their plasmonic properties for biomedical applications," Chem. Soc. Rev. 35, 1084-1094 (2006).
[CrossRef] [PubMed]

Li, Z. Y.

L. Gao, K. W. Yu, Z. Y. Li, and B. Hu, "Effective nonlinear optical properties of metal-dielectric composite media with shape distribution," Phys. Rev. E 64, 036615 (2001).
[CrossRef]

Li, Z. -Y.

B. J. Wiley, Y. Chen, J. M. McLellan, Y. Xiong, Z. -Y. Li, D. Ginger, and Y. Xia, "Synthesis and optical properties of silver nanobars and nanorice," Nano Lett. 7, 1032-1036 (2007).
[CrossRef] [PubMed]

M. Hu, J. Chen, Z. -Y. Li, L. Au, G. V. Hartland, X. Li, M. Marquez, and Y. Xia, "Gold nanostructures: Engineering their plasmonic properties for biomedical applications," Chem. Soc. Rev. 35, 1084-1094 (2006).
[CrossRef] [PubMed]

B. J. Willey, Y. Xiong, Z. -Y. Li, Y. Yin, and Y. N. Xia, "Right bipyramids of silver: a new shape derived from single twinned seeds," Nano Lett. 6, 765-768 (2006).
[CrossRef]

Lin, Y. -W.

Y. -F. Huang, Y. -W. Lin, and H. -T. Chang, "Growth of various Au-Ag nanocomposites from gold seeds in amino acid solutions," Nanotechnology 17, 4885-4894 (2006).
[CrossRef]

Link, S.

M. B. Mohamed, V. Volkov, S. Link, and M. A. 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]

Liu, M.

M. Liu and P. Guyot-Sionnest, "Synthesis and optical characterization of Au/Ag core/shell nanorods," J. Phys. Chem. B 108, 5882-5888 (2004).
[CrossRef]

Liu, S. D.

S. D. Liu, M. T. Cheng, Z. J. Yang, and Q. Q. Wang, "Surface plasmon propagation in a pair of metal nanowires coupled to a nanosized optical emitter," Opt. Lett. 33, 851-853 (2008).
[CrossRef] [PubMed]

M. T. Cheng, S. D. Liu, and Q. Q. Wang, "Modulating emission polarization of semiconductor quantum dots through surface plasmon of metal nanorod," Appl. Phys. Lett. 92, 162107 (2008).
[CrossRef]

Louis, C.

C. Louis, S. Roux, G. Ledoux, L. Lemelle, P. Gillet, O. Tillement, and P. Perriat, "Gold nano-antennas for increasing luminescence," Adv. Mater. 16, 2163-2166 (2004).
[CrossRef]

Lyandres, O.

J. N. Anker, W. P. Hall, O. Lyandres, N. C. Shah, J. Zhao, and R. P. van Duyne, "Biosensing with plasmonic nanosensors," Nat. Mater. 7, 442-453 (2008).
[CrossRef] [PubMed]

Marquez, M.

M. Hu, J. Chen, Z. -Y. Li, L. Au, G. V. Hartland, X. Li, M. Marquez, and Y. Xia, "Gold nanostructures: Engineering their plasmonic properties for biomedical applications," Chem. Soc. Rev. 35, 1084-1094 (2006).
[CrossRef] [PubMed]

Martin, O. J. F.

P. Muhlschlegel, H. J. Eisler, O. J. F. Martin, B. Hecht, and D. W. Pohl, "Resonant optical antennas," Science 308, 1607-1609 (2005).
[CrossRef] [PubMed]

McFarland, A. D.

A. J. Haes, C. L. Haynes, A. D. McFarland, G. C. Schatz, R. P. Van Duyne, and S. L. Zou, "Plasmonic materials for surface-enhanced sensing and spectroscopy," MRS Bull. 30, 368-375 (2005).
[CrossRef]

McLellan, J. M.

B. J. Wiley, Y. Chen, J. M. McLellan, Y. Xiong, Z. -Y. Li, D. Ginger, and Y. Xia, "Synthesis and optical properties of silver nanobars and nanorice," Nano Lett. 7, 1032-1036 (2007).
[CrossRef] [PubMed]

J. M. McLellan, A. Siekkinen, J. Chen, and Y. Xia, "Comparison of the surface-enhanced Raman scattering on sharp and truncated silver nanocubes," Chem. Phys. Lett. 427, 122-126 (2006).
[CrossRef]

Moerner, W. E.

A. Sundaramurthy, P. J. Schuck, N. R. Conley, D. P. Fromm, G. S. Kino, and W. E. Moerner, "Toward nanometer-scale optical photolithography: utilizing the near-field of bowtie optical nanoantennas," Nano Lett. 6, 355-360 (2006).
[CrossRef] [PubMed]

Mohamed, M. B.

M. B. Mohamed, V. Volkov, S. Link, and M. A. 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]

Motamedi, M.

M. Eghtedari, A. Oraevsky, J. A. Copland, N. A. Kotov, A. Conjusteau, and M. Motamedi, "High sensitivity of in vivo detection of gold nanorods using a laser optoacoustic imaging system," Nano Lett. 7, 1914-1918 (2007).
[CrossRef] [PubMed]

Muhlschlegel, P.

P. Muhlschlegel, H. J. Eisler, O. J. F. Martin, B. Hecht, and D. W. Pohl, "Resonant optical antennas," Science 308, 1607-1609 (2005).
[CrossRef] [PubMed]

Nehl, C. L.

F. Hao, C. L. Nehl, J. H. Hafner, and P. Nordlander, "Plasmon resonances of a gold nanostar," Nano Lett. 7, 729-732 (2007).
[CrossRef] [PubMed]

Ni, W.

X. Kou, W. Ni, C. -K. Tsung, K. Chan, H. -Q, Lin, G. D. Stucky, and J. Wang, "Growth of gold bipyramids with improved yield and their curvature-directed oxidation," Small 3, 2103-2113 (2007).
[CrossRef] [PubMed]

Nikoobakht, B.

B. Nikoobakht and M. A. El-Sayed, "Preparation and growth mechanism of gold nanorods(NRs) using seed-mediated growth method," Chem. Mater. 15, 1957-1962 (2003).
[CrossRef]

Nordlander, P.

F. Hao, C. L. Nehl, J. H. Hafner, and P. Nordlander, "Plasmon resonances of a gold nanostar," Nano Lett. 7, 729-732 (2007).
[CrossRef] [PubMed]

H. Wang, D. W. Brandl, F. Le, P. Nordlander, and N. J. Halas, "Nanorice: a hybrid plasmonic nanostructure," Nano Lett. 6, 827-832 (2006).
[CrossRef] [PubMed]

Oraevsky, A.

M. Eghtedari, A. Oraevsky, J. A. Copland, N. A. Kotov, A. Conjusteau, and M. Motamedi, "High sensitivity of in vivo detection of gold nanorods using a laser optoacoustic imaging system," Nano Lett. 7, 1914-1918 (2007).
[CrossRef] [PubMed]

Park, I. Y.

S. Kim, J. Jin, Y. J. Kim, I. Y. Park, Y. Kim, and S. W. Kim, "High-harmonic generation by resonant plasmon field enhancement," Nature 453, 757-760 (2008).
[CrossRef] [PubMed]

Perriat, P.

C. Louis, S. Roux, G. Ledoux, L. Lemelle, P. Gillet, O. Tillement, and P. Perriat, "Gold nano-antennas for increasing luminescence," Adv. Mater. 16, 2163-2166 (2004).
[CrossRef]

Pohl, D. W.

P. Muhlschlegel, H. J. Eisler, O. J. F. Martin, B. Hecht, and D. W. Pohl, "Resonant optical antennas," Science 308, 1607-1609 (2005).
[CrossRef] [PubMed]

Raynaud, M.

J. Kupersztych and M. Raynaud, "Anomalous multiphoton photoelectric effect in ultrashort time scales," Phys. Rev. Lett. 95, 147401 (2005).
[CrossRef] [PubMed]

Ren, J. J.

Q. Q. Wang, J. B. Han, H. M. Gong, D. J. Chen, X. J. Zhao, J. Y. Feng, and J. J. Ren, "Linear and nonlinear optical properties of Ag nanowire polarizing glass," Adv. Funct. Mater. 16, 2405-2408 (2006).
[CrossRef]

Roux, S.

C. Louis, S. Roux, G. Ledoux, L. Lemelle, P. Gillet, O. Tillement, and P. Perriat, "Gold nano-antennas for increasing luminescence," Adv. Mater. 16, 2163-2166 (2004).
[CrossRef]

Said, A. A.

M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, "Sensitive measurements of anisotropy of nonlinear refraction and absorption in crystals," IEEE J. Quantum Electron. 26, 760-769 (1990).
[CrossRef]

Schatz, G. C.

A. J. Haes, C. L. Haynes, A. D. McFarland, G. C. Schatz, R. P. Van Duyne, and S. L. Zou, "Plasmonic materials for surface-enhanced sensing and spectroscopy," MRS Bull. 30, 368-375 (2005).
[CrossRef]

Schubert, O.

J. Becker, I. Zins, A. Jakab, Y. Khalavka, O. Schubert, and C. Sönnichsen, "Plasmonic focusing reduces ensemble linewidth of silver-coated gold nanorods," Nano Lett. 8, 1719-1723 (2008).
[CrossRef] [PubMed]

Schuck, P. J.

A. Sundaramurthy, P. J. Schuck, N. R. Conley, D. P. Fromm, G. S. Kino, and W. E. Moerner, "Toward nanometer-scale optical photolithography: utilizing the near-field of bowtie optical nanoantennas," Nano Lett. 6, 355-360 (2006).
[CrossRef] [PubMed]

Scott, R. W. J.

O. M. Wilson, R. W. J. Scott, J. C. Garcia-Martinez, and R. M. Crooks, "Synthesis, characterization, and structure-selective extraction of 1-3nm diameter AuAg dendrimer-encapsulated bimetallic nanoparticles," J. Am. Chem. Soc. 127, 1015-1024 (2005).
[CrossRef] [PubMed]

Shah, N. C.

J. N. Anker, W. P. Hall, O. Lyandres, N. C. Shah, J. Zhao, and R. P. van Duyne, "Biosensing with plasmonic nanosensors," Nat. Mater. 7, 442-453 (2008).
[CrossRef] [PubMed]

Shanmukh, S.

S. B. Chaney, S. Shanmukh, and R. A. Dluhy, "Aligned silver nanorod arrays produce high sensitivity SERS substrates," Appl. Phys. Lett. 87, 031908 (2005).
[CrossRef]

Sheik-Bahae, M.

M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, "Sensitive measurements of anisotropy of nonlinear refraction and absorption in crystals," IEEE J. Quantum Electron. 26, 760-769 (1990).
[CrossRef]

Siekkinen, A.

J. M. McLellan, A. Siekkinen, J. Chen, and Y. Xia, "Comparison of the surface-enhanced Raman scattering on sharp and truncated silver nanocubes," Chem. Phys. Lett. 427, 122-126 (2006).
[CrossRef]

Sönnichsen, C.

J. Becker, I. Zins, A. Jakab, Y. Khalavka, O. Schubert, and C. Sönnichsen, "Plasmonic focusing reduces ensemble linewidth of silver-coated gold nanorods," Nano Lett. 8, 1719-1723 (2008).
[CrossRef] [PubMed]

Sundaramurthy, A.

A. Sundaramurthy, P. J. Schuck, N. R. Conley, D. P. Fromm, G. S. Kino, and W. E. Moerner, "Toward nanometer-scale optical photolithography: utilizing the near-field of bowtie optical nanoantennas," Nano Lett. 6, 355-360 (2006).
[CrossRef] [PubMed]

Tillement, O.

C. Louis, S. Roux, G. Ledoux, L. Lemelle, P. Gillet, O. Tillement, and P. Perriat, "Gold nano-antennas for increasing luminescence," Adv. Mater. 16, 2163-2166 (2004).
[CrossRef]

Tsung, C. -K.

X. Kou, W. Ni, C. -K. Tsung, K. Chan, H. -Q, Lin, G. D. Stucky, and J. Wang, "Growth of gold bipyramids with improved yield and their curvature-directed oxidation," Small 3, 2103-2113 (2007).
[CrossRef] [PubMed]

van Duyne, R. P.

J. N. Anker, W. P. Hall, O. Lyandres, N. C. Shah, J. Zhao, and R. P. van Duyne, "Biosensing with plasmonic nanosensors," Nat. Mater. 7, 442-453 (2008).
[CrossRef] [PubMed]

A. J. Haes, C. L. Haynes, A. D. McFarland, G. C. Schatz, R. P. Van Duyne, and S. L. Zou, "Plasmonic materials for surface-enhanced sensing and spectroscopy," MRS Bull. 30, 368-375 (2005).
[CrossRef]

Van Stryland, E. W.

M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, "Sensitive measurements of anisotropy of nonlinear refraction and absorption in crystals," IEEE J. Quantum Electron. 26, 760-769 (1990).
[CrossRef]

Volkov, V.

M. B. Mohamed, V. Volkov, S. Link, and M. A. 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]

Wang, H.

H. Wang, D. W. Brandl, F. Le, P. Nordlander, and N. J. Halas, "Nanorice: a hybrid plasmonic nanostructure," Nano Lett. 6, 827-832 (2006).
[CrossRef] [PubMed]

Wang, Q. Q.

M. T. Cheng, S. D. Liu, and Q. Q. Wang, "Modulating emission polarization of semiconductor quantum dots through surface plasmon of metal nanorod," Appl. Phys. Lett. 92, 162107 (2008).
[CrossRef]

S. D. Liu, M. T. Cheng, Z. J. Yang, and Q. Q. Wang, "Surface plasmon propagation in a pair of metal nanowires coupled to a nanosized optical emitter," Opt. Lett. 33, 851-853 (2008).
[CrossRef] [PubMed]

Q. Q. Wang, J. B. Han, D. L. Guo, S. Xiao, Y. B. Han, H. M. Gong, and X. W. Zou, "Highly efficient avalanche multiphoton luminescence from coupled Au nanowires in the visible region," Nano Lett. 7, 723-728 (2007).
[CrossRef] [PubMed]

Q. Q. Wang, J. B. Han, H. M. Gong, D. J. Chen, X. J. Zhao, J. Y. Feng, and J. J. Ren, "Linear and nonlinear optical properties of Ag nanowire polarizing glass," Adv. Funct. Mater. 16, 2405-2408 (2006).
[CrossRef]

J. B. Han, D. J. Chen, S. Ding, H. J. Zhou, Y. B. Han, G. G. Xiong, and Q. Q. Wang, "Plasmon resonant absorption and third-order optical nonlinearity in Ag-Ti cosputtered composite films," J. Appl. Phys. 99, 023526 (2006).
[CrossRef]

Wei, T. H.

M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, "Sensitive measurements of anisotropy of nonlinear refraction and absorption in crystals," IEEE J. Quantum Electron. 26, 760-769 (1990).
[CrossRef]

Wiley, B.

S. H. Im, Y. T. Lee, B. Wiley, and Y. N. Xia, "Large-scalesynthesis of silver nanocubes: the role of HCl in promotingcu be perfection and monodispersity," Angew. Chem. Int. Ed. 44, 2154-2157 (2005).
[CrossRef]

Wiley, B. J.

B. J. Wiley, Y. Chen, J. M. McLellan, Y. Xiong, Z. -Y. Li, D. Ginger, and Y. Xia, "Synthesis and optical properties of silver nanobars and nanorice," Nano Lett. 7, 1032-1036 (2007).
[CrossRef] [PubMed]

Willey, B. J.

B. J. Willey, Y. Xiong, Z. -Y. Li, Y. Yin, and Y. N. Xia, "Right bipyramids of silver: a new shape derived from single twinned seeds," Nano Lett. 6, 765-768 (2006).
[CrossRef]

Wilson, O. M.

O. M. Wilson, R. W. J. Scott, J. C. Garcia-Martinez, and R. M. Crooks, "Synthesis, characterization, and structure-selective extraction of 1-3nm diameter AuAg dendrimer-encapsulated bimetallic nanoparticles," J. Am. Chem. Soc. 127, 1015-1024 (2005).
[CrossRef] [PubMed]

Wu, Q. S.

L. Y. Cheng, Y. Chen, and Q. S. Wu, "Morphology exchange and optical properties of monodispersed ZnS nanospheres and nanoshuttles," Acta Chim. Sinica 17, 1851-1854 (2007).

Xia, Y.

B. J. Wiley, Y. Chen, J. M. McLellan, Y. Xiong, Z. -Y. Li, D. Ginger, and Y. Xia, "Synthesis and optical properties of silver nanobars and nanorice," Nano Lett. 7, 1032-1036 (2007).
[CrossRef] [PubMed]

J. M. McLellan, A. Siekkinen, J. Chen, and Y. Xia, "Comparison of the surface-enhanced Raman scattering on sharp and truncated silver nanocubes," Chem. Phys. Lett. 427, 122-126 (2006).
[CrossRef]

M. Hu, J. Chen, Z. -Y. Li, L. Au, G. V. Hartland, X. Li, M. Marquez, and Y. Xia, "Gold nanostructures: Engineering their plasmonic properties for biomedical applications," Chem. Soc. Rev. 35, 1084-1094 (2006).
[CrossRef] [PubMed]

Xia, Y. N.

B. J. Willey, Y. Xiong, Z. -Y. Li, Y. Yin, and Y. N. Xia, "Right bipyramids of silver: a new shape derived from single twinned seeds," Nano Lett. 6, 765-768 (2006).
[CrossRef]

S. H. Im, Y. T. Lee, B. Wiley, and Y. N. Xia, "Large-scalesynthesis of silver nanocubes: the role of HCl in promotingcu be perfection and monodispersity," Angew. Chem. Int. Ed. 44, 2154-2157 (2005).
[CrossRef]

Xiao, S.

Q. Q. Wang, J. B. Han, D. L. Guo, S. Xiao, Y. B. Han, H. M. Gong, and X. W. Zou, "Highly efficient avalanche multiphoton luminescence from coupled Au nanowires in the visible region," Nano Lett. 7, 723-728 (2007).
[CrossRef] [PubMed]

Xiong, G. G.

J. B. Han, D. J. Chen, S. Ding, H. J. Zhou, Y. B. Han, G. G. Xiong, and Q. Q. Wang, "Plasmon resonant absorption and third-order optical nonlinearity in Ag-Ti cosputtered composite films," J. Appl. Phys. 99, 023526 (2006).
[CrossRef]

Xiong, Y.

B. J. Wiley, Y. Chen, J. M. McLellan, Y. Xiong, Z. -Y. Li, D. Ginger, and Y. Xia, "Synthesis and optical properties of silver nanobars and nanorice," Nano Lett. 7, 1032-1036 (2007).
[CrossRef] [PubMed]

B. J. Willey, Y. Xiong, Z. -Y. Li, Y. Yin, and Y. N. Xia, "Right bipyramids of silver: a new shape derived from single twinned seeds," Nano Lett. 6, 765-768 (2006).
[CrossRef]

Yang, Z.

C. -C. Huang, Z. Yang, and H. -T. Chang, "Synthesis of dumbbell-shaped Au-Ag Core-Shell nanorods by seed-mediated growth under alkaline conditions," Langmuir 20, 6089-6092 (2004).
[CrossRef] [PubMed]

Yang, Z. J.

Yin, Y.

B. J. Willey, Y. Xiong, Z. -Y. Li, Y. Yin, and Y. N. Xia, "Right bipyramids of silver: a new shape derived from single twinned seeds," Nano Lett. 6, 765-768 (2006).
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Yu, K. W.

L. Gao, K. W. Yu, Z. Y. Li, and B. Hu, "Effective nonlinear optical properties of metal-dielectric composite media with shape distribution," Phys. Rev. E 64, 036615 (2001).
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Zhao, J.

J. N. Anker, W. P. Hall, O. Lyandres, N. C. Shah, J. Zhao, and R. P. van Duyne, "Biosensing with plasmonic nanosensors," Nat. Mater. 7, 442-453 (2008).
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Zhao, X. J.

Q. Q. Wang, J. B. Han, H. M. Gong, D. J. Chen, X. J. Zhao, J. Y. Feng, and J. J. Ren, "Linear and nonlinear optical properties of Ag nanowire polarizing glass," Adv. Funct. Mater. 16, 2405-2408 (2006).
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Zhou, H. J.

J. B. Han, D. J. Chen, S. Ding, H. J. Zhou, Y. B. Han, G. G. Xiong, and Q. Q. Wang, "Plasmon resonant absorption and third-order optical nonlinearity in Ag-Ti cosputtered composite films," J. Appl. Phys. 99, 023526 (2006).
[CrossRef]

Zins, I.

J. Becker, I. Zins, A. Jakab, Y. Khalavka, O. Schubert, and C. Sönnichsen, "Plasmonic focusing reduces ensemble linewidth of silver-coated gold nanorods," Nano Lett. 8, 1719-1723 (2008).
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Zou, S. L.

A. J. Haes, C. L. Haynes, A. D. McFarland, G. C. Schatz, R. P. Van Duyne, and S. L. Zou, "Plasmonic materials for surface-enhanced sensing and spectroscopy," MRS Bull. 30, 368-375 (2005).
[CrossRef]

Zou, X. W.

Q. Q. Wang, J. B. Han, D. L. Guo, S. Xiao, Y. B. Han, H. M. Gong, and X. W. Zou, "Highly efficient avalanche multiphoton luminescence from coupled Au nanowires in the visible region," Nano Lett. 7, 723-728 (2007).
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Acta Chim. Sinica

L. Y. Cheng, Y. Chen, and Q. S. Wu, "Morphology exchange and optical properties of monodispersed ZnS nanospheres and nanoshuttles," Acta Chim. Sinica 17, 1851-1854 (2007).

Adv. Funct. Mater.

Q. Q. Wang, J. B. Han, H. M. Gong, D. J. Chen, X. J. Zhao, J. Y. Feng, and J. J. Ren, "Linear and nonlinear optical properties of Ag nanowire polarizing glass," Adv. Funct. Mater. 16, 2405-2408 (2006).
[CrossRef]

Adv. Mater.

C. Louis, S. Roux, G. Ledoux, L. Lemelle, P. Gillet, O. Tillement, and P. Perriat, "Gold nano-antennas for increasing luminescence," Adv. Mater. 16, 2163-2166 (2004).
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Angew. Chem. Int. Ed.

S. H. Im, Y. T. Lee, B. Wiley, and Y. N. Xia, "Large-scalesynthesis of silver nanocubes: the role of HCl in promotingcu be perfection and monodispersity," Angew. Chem. Int. Ed. 44, 2154-2157 (2005).
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Appl. Phys. Lett.

M. T. Cheng, S. D. Liu, and Q. Q. Wang, "Modulating emission polarization of semiconductor quantum dots through surface plasmon of metal nanorod," Appl. Phys. Lett. 92, 162107 (2008).
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S. B. Chaney, S. Shanmukh, and R. A. Dluhy, "Aligned silver nanorod arrays produce high sensitivity SERS substrates," Appl. Phys. Lett. 87, 031908 (2005).
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Chem. Mater.

B. Nikoobakht and M. A. El-Sayed, "Preparation and growth mechanism of gold nanorods(NRs) using seed-mediated growth method," Chem. Mater. 15, 1957-1962 (2003).
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Chem. Phys. Lett.

M. B. Mohamed, V. Volkov, S. Link, and M. A. El-Sayed, "The lightning gold nanorods: fluorescence enhancement of over a million compared to the gold metal," Chem. Phys. Lett. 317, 517-523 (2000).
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J. M. McLellan, A. Siekkinen, J. Chen, and Y. Xia, "Comparison of the surface-enhanced Raman scattering on sharp and truncated silver nanocubes," Chem. Phys. Lett. 427, 122-126 (2006).
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Chem. Soc. Rev.

M. Hu, J. Chen, Z. -Y. Li, L. Au, G. V. Hartland, X. Li, M. Marquez, and Y. Xia, "Gold nanostructures: Engineering their plasmonic properties for biomedical applications," Chem. Soc. Rev. 35, 1084-1094 (2006).
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IEEE J. Quantum Electron.

M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, "Sensitive measurements of anisotropy of nonlinear refraction and absorption in crystals," IEEE J. Quantum Electron. 26, 760-769 (1990).
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J. Am. Chem. Soc.

O. M. Wilson, R. W. J. Scott, J. C. Garcia-Martinez, and R. M. Crooks, "Synthesis, characterization, and structure-selective extraction of 1-3nm diameter AuAg dendrimer-encapsulated bimetallic nanoparticles," J. Am. Chem. Soc. 127, 1015-1024 (2005).
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J. Appl. Phys.

J. B. Han, D. J. Chen, S. Ding, H. J. Zhou, Y. B. Han, G. G. Xiong, and Q. Q. Wang, "Plasmon resonant absorption and third-order optical nonlinearity in Ag-Ti cosputtered composite films," J. Appl. Phys. 99, 023526 (2006).
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J. Phys. Chem. B

M. Liu and P. Guyot-Sionnest, "Synthesis and optical characterization of Au/Ag core/shell nanorods," J. Phys. Chem. B 108, 5882-5888 (2004).
[CrossRef]

Langmuir

C. -C. Huang, Z. Yang, and H. -T. Chang, "Synthesis of dumbbell-shaped Au-Ag Core-Shell nanorods by seed-mediated growth under alkaline conditions," Langmuir 20, 6089-6092 (2004).
[CrossRef] [PubMed]

MRS Bull.

A. J. Haes, C. L. Haynes, A. D. McFarland, G. C. Schatz, R. P. Van Duyne, and S. L. Zou, "Plasmonic materials for surface-enhanced sensing and spectroscopy," MRS Bull. 30, 368-375 (2005).
[CrossRef]

Nano Lett.

B. J. Wiley, Y. Chen, J. M. McLellan, Y. Xiong, Z. -Y. Li, D. Ginger, and Y. Xia, "Synthesis and optical properties of silver nanobars and nanorice," Nano Lett. 7, 1032-1036 (2007).
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H. Wang, D. W. Brandl, F. Le, P. Nordlander, and N. J. Halas, "Nanorice: a hybrid plasmonic nanostructure," Nano Lett. 6, 827-832 (2006).
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M. Eghtedari, A. Oraevsky, J. A. Copland, N. A. Kotov, A. Conjusteau, and M. Motamedi, "High sensitivity of in vivo detection of gold nanorods using a laser optoacoustic imaging system," Nano Lett. 7, 1914-1918 (2007).
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R. A. Farrer, F. L. Butterfield, V. W. Chen, and J. T. Fourkas, "Highly efficient multiphoton-absorption-induced luminescence from gold nanoparticles," Nano Lett. 5, 1139-1142 (2005).
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F. Hao, C. L. Nehl, J. H. Hafner, and P. Nordlander, "Plasmon resonances of a gold nanostar," Nano Lett. 7, 729-732 (2007).
[CrossRef] [PubMed]

Q. Q. Wang, J. B. Han, D. L. Guo, S. Xiao, Y. B. Han, H. M. Gong, and X. W. Zou, "Highly efficient avalanche multiphoton luminescence from coupled Au nanowires in the visible region," Nano Lett. 7, 723-728 (2007).
[CrossRef] [PubMed]

B. J. Willey, Y. Xiong, Z. -Y. Li, Y. Yin, and Y. N. Xia, "Right bipyramids of silver: a new shape derived from single twinned seeds," Nano Lett. 6, 765-768 (2006).
[CrossRef]

A. Sundaramurthy, P. J. Schuck, N. R. Conley, D. P. Fromm, G. S. Kino, and W. E. Moerner, "Toward nanometer-scale optical photolithography: utilizing the near-field of bowtie optical nanoantennas," Nano Lett. 6, 355-360 (2006).
[CrossRef] [PubMed]

J. Becker, I. Zins, A. Jakab, Y. Khalavka, O. Schubert, and C. Sönnichsen, "Plasmonic focusing reduces ensemble linewidth of silver-coated gold nanorods," Nano Lett. 8, 1719-1723 (2008).
[CrossRef] [PubMed]

Nanotechnology

Y. -F. Huang, Y. -W. Lin, and H. -T. Chang, "Growth of various Au-Ag nanocomposites from gold seeds in amino acid solutions," Nanotechnology 17, 4885-4894 (2006).
[CrossRef]

Nat. Mater.

J. N. Anker, W. P. Hall, O. Lyandres, N. C. Shah, J. Zhao, and R. P. van Duyne, "Biosensing with plasmonic nanosensors," Nat. Mater. 7, 442-453 (2008).
[CrossRef] [PubMed]

Nature

S. Kim, J. Jin, Y. J. Kim, I. Y. Park, Y. Kim, and S. W. Kim, "High-harmonic generation by resonant plasmon field enhancement," Nature 453, 757-760 (2008).
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Phys. Rev. E

L. Gao, K. W. Yu, Z. Y. Li, and B. Hu, "Effective nonlinear optical properties of metal-dielectric composite media with shape distribution," Phys. Rev. E 64, 036615 (2001).
[CrossRef]

Phys. Rev. Lett.

J. Kupersztych and M. Raynaud, "Anomalous multiphoton photoelectric effect in ultrashort time scales," Phys. Rev. Lett. 95, 147401 (2005).
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Science

P. Muhlschlegel, H. J. Eisler, O. J. F. Martin, B. Hecht, and D. W. Pohl, "Resonant optical antennas," Science 308, 1607-1609 (2005).
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Figures (4)

Fig. 1.
Fig. 1.

(a), (b) TEM images of Au NRs and Au/Ag nanoshuttles, respectively. (c) HRTEM image of one Au/Ag nanoshuttle.

Fig. 2.
Fig. 2.

Calculated (a) and experimental (b) extinction spectra of Au NRs and Au/Ag nanoshuttles with insets giving TEM images, respectively.

Fig. 3.
Fig. 3.

Resonant enhancement of local fields obtained from FDTD calculations of the averagely sized Au NR (a) and Au/Ag nanoshuttle (b) at a mesh size of 0.2 nm. (c) Electric field enhancement profiles along the longitudinal direction for (a) Au NR and (b) Au/Ag nanoshuttle. The origin is at their centers. They are excited at their respective LSP peak wavelengths and polarization parallel to the long axis.

Fig. 4.
Fig. 4.

Enhanced third-order optical nonlinearity of Au NRs and Au/Ag nanoshuttles: (a), (b) Open- and closed-aperture Z-scans of Au NRs and Au/Ag nanoshuttles when their NLR reaches the maxima around the corresponding LSPRs (λexc(Au)=860 nm, λ exc(Au/Ag)=760 nm). The scatter open circles are experimental data while the solid lines are the fitting curves by using the standard Z-scan theory. (c) The value of χ (3) vs the excitation wavelength.

Equations (2)

Equations on this page are rendered with MathJax. Learn more.

T OP = m = 0 ( q 0 ) m ( 1 + z 2 z 0 2 ) m ( 1 + m ) 3 2
T CL T OP = 1 + 4 Δ ϕ 0 z z 0 ( ( z z 0 ) 2 + 9 ) ( ( z z 0 ) 2 + 1 )

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