Abstract

The plasmon resonance-based optical trapping (PREBOT) method is used to achieve stable trapping of metallic nanoparticles of different shapes and composition, including Au bipyramids and Au/Ag core/shell nanorods. In all cases the longitudinal plasmon mode of these anisotropic particles is used to enhance the gradient force of an optical trap, thereby increasing the strength of the trap potential. Specifically, the trapping laser is slightly detuned to the long-wavelength side of the longitudinal plasmon resonance where the sign of the real component of the polarizability leads to an attractive gradient force. A second (femtosecond pulsed) laser is used to excite two-photon fluorescence for detection of the trapped nanoparticles. Two-photon fluorescence time trajectories are recorded for up to 20 minutes for single and multiple particles in the trap. In the latter case, a stepwise increase reflects sequential loading of single Au bipyramids. The nonlinearity of the amplitude and noise with step number are interpreted as arising from interactions or enhanced local fields amongst the trapped particles and fluctuations in the arrangements thereof.

© 2007 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |

  1. A. Ashkin, J. M. Dziedzic, J. E. Bjorkholm, S. Chu, "Observation of a single-beam gradient force optical trap for dielectric particles," Opt. Lett. 11, 288-290 (1986).
    [CrossRef] [PubMed]
  2. A. Ashkin, "Optical trapping and manipulation of neutral particles using lasers," Proc. Natl. Acad. Sci. 94, 4853-4860 (1997).
    [CrossRef] [PubMed]
  3. A. Ashkin, Optical trapping and manipulation of neutral particles using lasers, World Scientific (2006).
    [CrossRef]
  4. K. Dholakia and P. Reece, "Optical micromanipulation takes hold," Nano Today 1, 18-27 (2006).
    [CrossRef]
  5. D. G. Grier, "A revolution in optical manipulation," Nature 424, 810-816 (2003).
    [CrossRef] [PubMed]
  6. G. M. Wang, E. M. Sevick, E. Mittag, D. J. Searles, D. Evans, "Experimental demonstration of violations of the second law of thermodynamics for small systems and short time scales," Phys. Rev. Lett. 89, 050601 (2002).
    [CrossRef] [PubMed]
  7. M. D. Wang, J. M. Schnitzer, H. Yin, R. Landick, J. Gelles, S. M. Block, "Force and velocity measured for single molecules of RNA polymerase," Science 282, 902-907 (1998).
    [CrossRef] [PubMed]
  8. J. Liphardt, B. Onoa, S. B. Smith, I. Tinoco, Jr., C. Bustamante, "Reversible unfolding of single RNA molecules by mechanical force," Science 292, 733-737 (2001).
    [CrossRef] [PubMed]
  9. E. R. Dufresne and D. G. Grier, "Optical tweezer arrays and optical substrates created with diffractive optics," Rev. Sci. Instrum. 69, 1974-1977 (1998).
    [CrossRef]
  10. K. C. Neuman and S. M. Block, "Optical trapping," Rev. Sci. Instrum. 75, 2787-2809 (2004).
    [CrossRef]
  11. P. A. Prentice, M. P. MacDonald, T. G. Frank, A. Cuschieri, G. C. Spalding, W. Sibbett, P. A. Campbell, K. Dholakia,"Manipulation and filtration of low index particles with holographic Laguerre-Gaussian optical trap arrays," Opt. Express 12, 593-600 (2004).
    [CrossRef] [PubMed]
  12. K. Svoboda and S. M. Block, "Optical trapping of metallic Rayleigh particles," Opt. Lett. 19, 930-932 (1994).
    [CrossRef] [PubMed]
  13. A. Zelenina, R. Quidant, M. Nieto-Vesperinas, "Enhanced optical forces between coupled resonant metal nanoparticles," Opt. Lett. 32, 1156-1158 (2007).
    [CrossRef] [PubMed]
  14. ´ E. Lamothe, G. Lévêque, O. J. F. Martin, "Optical forces in coupled plasmonic nanosystems: near field and far field interaction regimes," Opt. Express 15, 9631-9644 (2007).
    [CrossRef] [PubMed]
  15. M. M. Burns, J.-M. Fournier, J. A. Golovchenko, "Optical binding," Phys. Rev. Lett. 63, 1233-1236 (1989).
    [CrossRef] [PubMed]
  16. J. Plewa, E. Tanner, D.M. Mueth, D. G. Grier, "Processing carbon nanotubes with holographic optical tweezers," Opt. Express 12, 1978-1981 (2004).
    [CrossRef] [PubMed]
  17. S. Tan, H. A. Lopez, C. W. Cai, Y. Zhang, "Optical trapping of single-walled carbon nanotubes," Nano Lett. 4, 1415-1419 (2004).
    [CrossRef]
  18. R. Agarwal, K. Ladavac, Y. Roichman, G. Yu, C. M. Lieber, D. G. Grier, "Manipulation and assembly of nanowires with holographic optical traps," Opt. Express 13, 8906-8912 (2005).
    [CrossRef] [PubMed]
  19. P. M. Hansen, V. K. Bhatia, N. Harrit, L. Oddershede, "Expanding the optical trapping range of gold nanoparticles," Nano Lett. 5, 1937-1942 (2005).
    [CrossRef] [PubMed]
  20. J. Prikulis, F. Svedberg, M. Käll, J. Enger, K. Ramser, M. Goksör, D. Hanstorp, "Optical spectroscopy of single trapped metal nanoparticles in solution," Nano Lett. 4, 115-118 (2004).
    [CrossRef]
  21. Y. Seol, A. E. Carpenter, T. T. Perkins, "Gold nanoparticles: Enhanced optical trapping and sensitivity coupled with significant heating," Opt. Lett. 31, 2429-2431 (2006).
    [CrossRef] [PubMed]
  22. A. Ashkin and J. M. Dziedzic, "Observation of resonances in the radiation pressure on dielectric spheres," Phys. Rev. Lett. 38, 1351-1354 (1977).
    [CrossRef]
  23. S. Chu, J. E. Bjorkholm, A. Ashkin, A. Cable, "Experimental observation of optically trapped atoms," Phys. Rev. Lett. 57, 314-317 (1986).
    [CrossRef] [PubMed]
  24. R. R. Agayan, F. Gittes, R. Kopelman, C. F. Schmidt, "Optical trapping near resonance absorption," Appl. Opt. 41, 2318-2327 (2002).
    [CrossRef]
  25. D. T. Chiu and R. N. Zare, "Biased diffusion, optical trapping, and manipulation of single molecules in solution," J. Am. Chem. Soc. 118, 6512-6513 (1996).
    [CrossRef]
  26. M. A. Osborne, S. Balabramanian, W. S. Furey, D. Klenerman, "Optically biased diffusion of single molecules studied by confocal fluorescence microscopy," J. Phys. Chem. B 102, 3160-3167 (1998).
    [CrossRef]
  27. T. Iida and H. Ishihara, "Theoretical study of the optical manipulation of semiconductor nanoparticles under an excitonic resonance condition," Phys. Rev. Lett. 90, 057403 (2003).
    [CrossRef] [PubMed]
  28. M. Pelton, "Comment on ‘Theoretical study of the optical manipulation of semiconductor nanoparticles under an excitonic resonance condition’," Phys. Rev. Lett. 92, 89701 (2004).
    [CrossRef]
  29. J. R. Arias-Gonzlez and M. Nieto-Vesperinas, "Optical forces on small particles: attractive and repulsive nature and plasmon-resonance conditions," J. Opt. Soc. Am A 20, 1201-1209 (2003).
    [CrossRef]
  30. A. S. Zelenina, R. Quidant, G. Cadenes, M. Nieto-Vesperinas, "Tunable optical sorting and manipulation of nanoparticles via plasmon excitation," Opt. Lett. 31, 2054-2056 (2006).
    [CrossRef] [PubMed]
  31. M. Pelton, M. Liu, S. Park, N. F. Scherer, P. Guyot-Sionnest, "Ultrafast resonant optical scattering from single gold nanorods: large nonlinearities and plasmon saturation," Phys. Rev. B 73, 155419 (2006).
    [CrossRef]
  32. C. F. Bohren and D. R. Huffman, Absorption and Scattering of Light by Small Particles, John Wiley & Sons (1983).
  33. M. Pelton, M. Liu, H. Y. Kim, G. Smith, P. Guyot-Sionnest, N. F. Scherer, "Optical trapping and alignment of single gold nanorods using plasmon resonances," Opt. Lett. 31, 2075-2077 (2006).
    [CrossRef] [PubMed]
  34. C. Sönnichsen, T. Franzl, T. Wilk, G. von Plessen, J. Feldmann, O. Wilson, P. Mulvaney, "Drastic reduction of plasmon damping in gold nanorods," Phys. Rev. Lett. 88, 077402 (2002).
    [CrossRef] [PubMed]
  35. U. Krebig and M. Volmer, Optical Properties of Metal Clusters, Springer (1995).
  36. L. Novotny and B. Hecht, Principles of Nano-Optics, Cambridge University Press (2006).
  37. 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]
  38. M. Liu and P. Guyot-Sionnest, "Mechanism of silver(I)-assisted growth of gold nanorods and bipyrmids," J. Phys. Chem. B 109, 22192-22200 (2005).
    [CrossRef]
  39. R. M. Dickson, D. J. Norris,W. E. Moerner, "Simultaneous imaging of individual molecules aligned both parallel and perpendicular to the optic axis," Phys. Rev. Lett. 81, 5322-5325 (1998).
    [CrossRef]
  40. H. Xu and M. Käll, "Surface-plasmon-enhanced optical forces in silver nanoaggregates," Phys. Rev. Lett. 89, 246802 (2002).
    [CrossRef] [PubMed]
  41. A. J. Hallock, P. L. Redmond, L. E. Brus, "Optical forces between metallic particles," Proc. Natl. Acad. Sci. 102, 1280-1284 (2005).
    [CrossRef] [PubMed]
  42. B. M. Reinhard, M. Siu, H. Agarwal, A. P. Alivisatos, J. Liphardt,"Calibration of dynamic molecular rulers based on plasmon coupling between gold nanoparticles," Nano Lett. 5, 2246-2252 (2005).
    [CrossRef] [PubMed]
  43. K. C. Toussaint, Jr., S. Park, J. E. Jureller, N. F. Scherer, "Generation of optical vector beams with a diffractive optical element interferometer," Opt. Lett. 30, 2846-2848 (2005).
    [CrossRef] [PubMed]
  44. B. Richards and E. Wolf, "Electromagnetic diffraction in optical systems. II. Structure of the image field in an aplanatic system," Proc. R. Soc. A. 253, 358-379 (1959).
    [CrossRef]

2007 (2)

2006 (5)

2005 (6)

M. Liu and P. Guyot-Sionnest, "Mechanism of silver(I)-assisted growth of gold nanorods and bipyrmids," J. Phys. Chem. B 109, 22192-22200 (2005).
[CrossRef]

A. J. Hallock, P. L. Redmond, L. E. Brus, "Optical forces between metallic particles," Proc. Natl. Acad. Sci. 102, 1280-1284 (2005).
[CrossRef] [PubMed]

B. M. Reinhard, M. Siu, H. Agarwal, A. P. Alivisatos, J. Liphardt,"Calibration of dynamic molecular rulers based on plasmon coupling between gold nanoparticles," Nano Lett. 5, 2246-2252 (2005).
[CrossRef] [PubMed]

K. C. Toussaint, Jr., S. Park, J. E. Jureller, N. F. Scherer, "Generation of optical vector beams with a diffractive optical element interferometer," Opt. Lett. 30, 2846-2848 (2005).
[CrossRef] [PubMed]

R. Agarwal, K. Ladavac, Y. Roichman, G. Yu, C. M. Lieber, D. G. Grier, "Manipulation and assembly of nanowires with holographic optical traps," Opt. Express 13, 8906-8912 (2005).
[CrossRef] [PubMed]

P. M. Hansen, V. K. Bhatia, N. Harrit, L. Oddershede, "Expanding the optical trapping range of gold nanoparticles," Nano Lett. 5, 1937-1942 (2005).
[CrossRef] [PubMed]

2004 (7)

J. Prikulis, F. Svedberg, M. Käll, J. Enger, K. Ramser, M. Goksör, D. Hanstorp, "Optical spectroscopy of single trapped metal nanoparticles in solution," Nano Lett. 4, 115-118 (2004).
[CrossRef]

S. Tan, H. A. Lopez, C. W. Cai, Y. Zhang, "Optical trapping of single-walled carbon nanotubes," Nano Lett. 4, 1415-1419 (2004).
[CrossRef]

M. Pelton, "Comment on ‘Theoretical study of the optical manipulation of semiconductor nanoparticles under an excitonic resonance condition’," Phys. Rev. Lett. 92, 89701 (2004).
[CrossRef]

K. C. Neuman and S. M. Block, "Optical trapping," Rev. Sci. Instrum. 75, 2787-2809 (2004).
[CrossRef]

P. A. Prentice, M. P. MacDonald, T. G. Frank, A. Cuschieri, G. C. Spalding, W. Sibbett, P. A. Campbell, K. Dholakia,"Manipulation and filtration of low index particles with holographic Laguerre-Gaussian optical trap arrays," Opt. Express 12, 593-600 (2004).
[CrossRef] [PubMed]

J. Plewa, E. Tanner, D.M. Mueth, D. G. Grier, "Processing carbon nanotubes with holographic optical tweezers," Opt. Express 12, 1978-1981 (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 (3)

D. G. Grier, "A revolution in optical manipulation," Nature 424, 810-816 (2003).
[CrossRef] [PubMed]

J. R. Arias-Gonzlez and M. Nieto-Vesperinas, "Optical forces on small particles: attractive and repulsive nature and plasmon-resonance conditions," J. Opt. Soc. Am A 20, 1201-1209 (2003).
[CrossRef]

T. Iida and H. Ishihara, "Theoretical study of the optical manipulation of semiconductor nanoparticles under an excitonic resonance condition," Phys. Rev. Lett. 90, 057403 (2003).
[CrossRef] [PubMed]

2002 (4)

G. M. Wang, E. M. Sevick, E. Mittag, D. J. Searles, D. Evans, "Experimental demonstration of violations of the second law of thermodynamics for small systems and short time scales," Phys. Rev. Lett. 89, 050601 (2002).
[CrossRef] [PubMed]

C. Sönnichsen, T. Franzl, T. Wilk, G. von Plessen, J. Feldmann, O. Wilson, P. Mulvaney, "Drastic reduction of plasmon damping in gold nanorods," Phys. Rev. Lett. 88, 077402 (2002).
[CrossRef] [PubMed]

H. Xu and M. Käll, "Surface-plasmon-enhanced optical forces in silver nanoaggregates," Phys. Rev. Lett. 89, 246802 (2002).
[CrossRef] [PubMed]

R. R. Agayan, F. Gittes, R. Kopelman, C. F. Schmidt, "Optical trapping near resonance absorption," Appl. Opt. 41, 2318-2327 (2002).
[CrossRef]

2001 (1)

J. Liphardt, B. Onoa, S. B. Smith, I. Tinoco, Jr., C. Bustamante, "Reversible unfolding of single RNA molecules by mechanical force," Science 292, 733-737 (2001).
[CrossRef] [PubMed]

1998 (4)

E. R. Dufresne and D. G. Grier, "Optical tweezer arrays and optical substrates created with diffractive optics," Rev. Sci. Instrum. 69, 1974-1977 (1998).
[CrossRef]

M. D. Wang, J. M. Schnitzer, H. Yin, R. Landick, J. Gelles, S. M. Block, "Force and velocity measured for single molecules of RNA polymerase," Science 282, 902-907 (1998).
[CrossRef] [PubMed]

M. A. Osborne, S. Balabramanian, W. S. Furey, D. Klenerman, "Optically biased diffusion of single molecules studied by confocal fluorescence microscopy," J. Phys. Chem. B 102, 3160-3167 (1998).
[CrossRef]

R. M. Dickson, D. J. Norris,W. E. Moerner, "Simultaneous imaging of individual molecules aligned both parallel and perpendicular to the optic axis," Phys. Rev. Lett. 81, 5322-5325 (1998).
[CrossRef]

1997 (1)

A. Ashkin, "Optical trapping and manipulation of neutral particles using lasers," Proc. Natl. Acad. Sci. 94, 4853-4860 (1997).
[CrossRef] [PubMed]

1996 (1)

D. T. Chiu and R. N. Zare, "Biased diffusion, optical trapping, and manipulation of single molecules in solution," J. Am. Chem. Soc. 118, 6512-6513 (1996).
[CrossRef]

1994 (1)

1989 (1)

M. M. Burns, J.-M. Fournier, J. A. Golovchenko, "Optical binding," Phys. Rev. Lett. 63, 1233-1236 (1989).
[CrossRef] [PubMed]

1986 (2)

A. Ashkin, J. M. Dziedzic, J. E. Bjorkholm, S. Chu, "Observation of a single-beam gradient force optical trap for dielectric particles," Opt. Lett. 11, 288-290 (1986).
[CrossRef] [PubMed]

S. Chu, J. E. Bjorkholm, A. Ashkin, A. Cable, "Experimental observation of optically trapped atoms," Phys. Rev. Lett. 57, 314-317 (1986).
[CrossRef] [PubMed]

1977 (1)

A. Ashkin and J. M. Dziedzic, "Observation of resonances in the radiation pressure on dielectric spheres," Phys. Rev. Lett. 38, 1351-1354 (1977).
[CrossRef]

1959 (1)

B. Richards and E. Wolf, "Electromagnetic diffraction in optical systems. II. Structure of the image field in an aplanatic system," Proc. R. Soc. A. 253, 358-379 (1959).
[CrossRef]

Appl. Opt. (1)

J. Am. Chem. Soc. (1)

D. T. Chiu and R. N. Zare, "Biased diffusion, optical trapping, and manipulation of single molecules in solution," J. Am. Chem. Soc. 118, 6512-6513 (1996).
[CrossRef]

J. Opt. Soc. Am A (1)

J. R. Arias-Gonzlez and M. Nieto-Vesperinas, "Optical forces on small particles: attractive and repulsive nature and plasmon-resonance conditions," J. Opt. Soc. Am A 20, 1201-1209 (2003).
[CrossRef]

J. Phys. Chem. B (3)

M. A. Osborne, S. Balabramanian, W. S. Furey, D. Klenerman, "Optically biased diffusion of single molecules studied by confocal fluorescence microscopy," J. Phys. Chem. B 102, 3160-3167 (1998).
[CrossRef]

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]

M. Liu and P. Guyot-Sionnest, "Mechanism of silver(I)-assisted growth of gold nanorods and bipyrmids," J. Phys. Chem. B 109, 22192-22200 (2005).
[CrossRef]

Nano Lett. (4)

B. M. Reinhard, M. Siu, H. Agarwal, A. P. Alivisatos, J. Liphardt,"Calibration of dynamic molecular rulers based on plasmon coupling between gold nanoparticles," Nano Lett. 5, 2246-2252 (2005).
[CrossRef] [PubMed]

S. Tan, H. A. Lopez, C. W. Cai, Y. Zhang, "Optical trapping of single-walled carbon nanotubes," Nano Lett. 4, 1415-1419 (2004).
[CrossRef]

P. M. Hansen, V. K. Bhatia, N. Harrit, L. Oddershede, "Expanding the optical trapping range of gold nanoparticles," Nano Lett. 5, 1937-1942 (2005).
[CrossRef] [PubMed]

J. Prikulis, F. Svedberg, M. Käll, J. Enger, K. Ramser, M. Goksör, D. Hanstorp, "Optical spectroscopy of single trapped metal nanoparticles in solution," Nano Lett. 4, 115-118 (2004).
[CrossRef]

Nano Today (1)

K. Dholakia and P. Reece, "Optical micromanipulation takes hold," Nano Today 1, 18-27 (2006).
[CrossRef]

Nature (1)

D. G. Grier, "A revolution in optical manipulation," Nature 424, 810-816 (2003).
[CrossRef] [PubMed]

Opt. Express (4)

Opt. Lett. (7)

Phys. Rev. B (1)

M. Pelton, M. Liu, S. Park, N. F. Scherer, P. Guyot-Sionnest, "Ultrafast resonant optical scattering from single gold nanorods: large nonlinearities and plasmon saturation," Phys. Rev. B 73, 155419 (2006).
[CrossRef]

Phys. Rev. Lett. (9)

C. Sönnichsen, T. Franzl, T. Wilk, G. von Plessen, J. Feldmann, O. Wilson, P. Mulvaney, "Drastic reduction of plasmon damping in gold nanorods," Phys. Rev. Lett. 88, 077402 (2002).
[CrossRef] [PubMed]

R. M. Dickson, D. J. Norris,W. E. Moerner, "Simultaneous imaging of individual molecules aligned both parallel and perpendicular to the optic axis," Phys. Rev. Lett. 81, 5322-5325 (1998).
[CrossRef]

H. Xu and M. Käll, "Surface-plasmon-enhanced optical forces in silver nanoaggregates," Phys. Rev. Lett. 89, 246802 (2002).
[CrossRef] [PubMed]

G. M. Wang, E. M. Sevick, E. Mittag, D. J. Searles, D. Evans, "Experimental demonstration of violations of the second law of thermodynamics for small systems and short time scales," Phys. Rev. Lett. 89, 050601 (2002).
[CrossRef] [PubMed]

A. Ashkin and J. M. Dziedzic, "Observation of resonances in the radiation pressure on dielectric spheres," Phys. Rev. Lett. 38, 1351-1354 (1977).
[CrossRef]

S. Chu, J. E. Bjorkholm, A. Ashkin, A. Cable, "Experimental observation of optically trapped atoms," Phys. Rev. Lett. 57, 314-317 (1986).
[CrossRef] [PubMed]

T. Iida and H. Ishihara, "Theoretical study of the optical manipulation of semiconductor nanoparticles under an excitonic resonance condition," Phys. Rev. Lett. 90, 057403 (2003).
[CrossRef] [PubMed]

M. Pelton, "Comment on ‘Theoretical study of the optical manipulation of semiconductor nanoparticles under an excitonic resonance condition’," Phys. Rev. Lett. 92, 89701 (2004).
[CrossRef]

M. M. Burns, J.-M. Fournier, J. A. Golovchenko, "Optical binding," Phys. Rev. Lett. 63, 1233-1236 (1989).
[CrossRef] [PubMed]

Proc. Natl. Acad. Sci. (2)

A. Ashkin, "Optical trapping and manipulation of neutral particles using lasers," Proc. Natl. Acad. Sci. 94, 4853-4860 (1997).
[CrossRef] [PubMed]

A. J. Hallock, P. L. Redmond, L. E. Brus, "Optical forces between metallic particles," Proc. Natl. Acad. Sci. 102, 1280-1284 (2005).
[CrossRef] [PubMed]

Proc. R. Soc. A. (1)

B. Richards and E. Wolf, "Electromagnetic diffraction in optical systems. II. Structure of the image field in an aplanatic system," Proc. R. Soc. A. 253, 358-379 (1959).
[CrossRef]

Rev. Sci. Instrum. (2)

E. R. Dufresne and D. G. Grier, "Optical tweezer arrays and optical substrates created with diffractive optics," Rev. Sci. Instrum. 69, 1974-1977 (1998).
[CrossRef]

K. C. Neuman and S. M. Block, "Optical trapping," Rev. Sci. Instrum. 75, 2787-2809 (2004).
[CrossRef]

Science (2)

M. D. Wang, J. M. Schnitzer, H. Yin, R. Landick, J. Gelles, S. M. Block, "Force and velocity measured for single molecules of RNA polymerase," Science 282, 902-907 (1998).
[CrossRef] [PubMed]

J. Liphardt, B. Onoa, S. B. Smith, I. Tinoco, Jr., C. Bustamante, "Reversible unfolding of single RNA molecules by mechanical force," Science 292, 733-737 (2001).
[CrossRef] [PubMed]

Other (4)

A. Ashkin, Optical trapping and manipulation of neutral particles using lasers, World Scientific (2006).
[CrossRef]

U. Krebig and M. Volmer, Optical Properties of Metal Clusters, Springer (1995).

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

C. F. Bohren and D. R. Huffman, Absorption and Scattering of Light by Small Particles, John Wiley & Sons (1983).

Supplementary Material (1)

» Media 1: AVI (2351 KB)     

Cited By

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

Alert me when this article is cited.


Figures (8)

Fig. 1.
Fig. 1.

Simulated: (a) absorption (red curve) and scattering (blue curve) cross-sections for the longitudinal plasmon mode of a single Au nanorod in water with aspect ratio 4.6 (15 nm×60 nm), (b) difference in magnitude between the cross-sections as the diameter of the long axis of the nanorods increases (and fixed aspect ratio 4.6), and (c) optical gradient force (red curve) and scattering force (black curve) acting on a Au nanorod with aspect ratio 4.6 (15 nm×60 nm). The model is valid in the dipole limit and assumes that the polarization of the optical field is parallel to the long axis of the rod.

Fig. 2.
Fig. 2.

PREBOT setup. Two lasers are used; one for trapping (solid red line) and one for probing (dashed orange line) of sample. The beam path used for trapping consists of lenses L 1 and L 2 of focal lengths 20 cm and 25 cm, respectively, and steering mirrors M 2 and M 3. Beam-pointing stability is maintained through the use of beam stabilizing mirrors (BSM 1 and BSM 2) and position-sensitive photodiodes (DET 1 and DET 2). The probe beam path has lenses L 3 and L 4 of equal focal length 5 cm, and steering mirror M 1. The beams are spatially combined at windowW before entering the microscope. LT is a tube lens of focal length 20 cm, and OBJ and S represent the water-immersion objective lens and sample, respectively. Two-photon fluorescence (green) is imaged using Li to either a CCD camera or APD detector. The polarization of the probe beam is kept linear. The power of the trap beam was kept constant at approximately 100 mWat the input to the microscope (with ~60 mW delivered to the sample) for all experiments reported here; the probe beam power was also kept constant at approximately 10 mW at the input to the microscope (with ~6 mW delivered to the sample).

Fig. 3.
Fig. 3.

TEM images and associated ensemble absorption spectra for (a) Au/Ag core/shell nanorods and (b) Au bipyramids in water. The scale bars are (a) 20 nm and (b) 10 nm, respectively.

Fig. 4.
Fig. 4.

Two-photon fluorescence time trajectories acquired for (a) Au/Ag core/shell nanorods, and (b) Au bipyramids integrating over 36×40 pixels and 66×60 pixels of the CCD, respectively. The slow drift in the fluorescence signal is attributed to the relative pointing instability of the trap and probe beams, which causes the axial location of the trap to change with respect to the probe beam focus. The instability is more severe for the Au/Ag particles since they are more difficult to trap due to their broad linewidths.

Fig. 5.
Fig. 5.

Time trace showing loading of Au bipyramids integrating over 66×60 pixels of the CCD. The numbers 0–6 label the stepwise signal level changes that occur as particles are progressively loaded into the trap. The inset is a linear-linear plot of the mean step height versus particle number with a fit to a polynomial y~xn ; n=1.6 (solid red line). The mean value for steps 0–6 are 0.017, 0.050, 0.356, 1.60, 3.10, 4.30, and 4.70, respectively, while the error bars represent the associated standard deviation for each step.

Fig. 6.
Fig. 6.

Histograms of instantaneous signals of Fig. 5 normalized to the mean values. Each distribution corresponds to the associated step number (and mean value) in Fig. 5.

Fig. 7.
Fig. 7.

(a) Sequential frames of a of a movie (100 ms integration time) of a particle entering the trap integrating over 40×40 pixels of the CCD. Each panel is intensity autoscaled and the panel number corresponds to each step in Fig. 5. (b) The associated radial profile plots (normalized to peak intensity). Note that the black curve in (b), corresponding to the first frame in (a), has a background contribution that is not insignificant in comparison to the signal from the particle.

Fig. 8.
Fig. 8.

Movie of multi-particle trapping integrating over 60×50 pixels of the CCD. [Media 1]

Tables (1)

Tables Icon

Table 1. Table of two-photon fluorescence normalized variance per step height for the histograms in Fig. 6. We define this normalized variance as the raw variance divided by the mean value of each step

Equations (4)

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

< F > = Re [ α ( ω ) ] 2 < E 2 > + n m c [ σ abs + σ scatt ] < E × B >
α ( ω ) = ε 0 V ε ( ω ) ε m ε m + [ ε ( ω ) ε m ] L j .
σ scatt ( ω ) = k 4 6 π ε o 2 α ( ω ) 2
σ abs ( ω ) = k ε o Im [ α ( ω ) ]

Metrics