Abstract

We investigate the limits of one-photon fluorescence as a contrast mechanism in nanoscale-resolution tip-enhanced optical microscopy. Specifically, we examine the magnitude of tip-induced signal enhancement needed to resolve individual fluorophores within densely-packed ensembles. Modulation of fluorescence signals induced by an oscillating tip followed by demodulation with a lock-in amplifier increases image contrast by nearly two orders of magnitude. A theoretical model of this simple modulation/ demodulation scheme predicts an optimal value for the tip-oscillation amplitude that agrees with experimental measurements. Further, as an important step toward the eventual application of tip-enhanced fluorescence microscopy to the nanoscale structural analysis of biomolecular systems, we show that requisite signal enhancement factors are within the capabilities of commercially available silicon tips.

© 2008 Optical Society of America

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History
Original Manuscript: February 12, 2008
Manuscript Accepted: April 14, 2008
Revised Manuscript: April 10, 2008
Published: April 17, 2008

References

1. L. Novotny, R. X. Bian, and X. S. Xie, "Theory of Nanometric Optical Tweezers," Phys. Rev. Lett. 79, 645-648 (1997). [CrossRef]
2. Z. Ma, J. M. Gerton, L. A. Wade, and S. R. Quake, "Fluorescence Near-Field Microscopy of DNA at Sub-10 nm Resolution," Phys. Rev. Lett. 97, 260801 (2006). [CrossRef]
3. H. G. Frey, S. Witt, K. Felderer, and R. Guckenberger, "High-resolution imaging of single fluorescent molecules with the optical near-field of a metal tip," Phys. Rev. Lett. 93, 200801 (2004). [CrossRef]
4. J. M. Gerton, L. A. Wade, G. A. Lessard, Z. Ma, and S. R. Quake, "Tip-enhanced fluorescence microscopy at 10 nanometer resolution," Phys. Rev. Lett. 93, 180801 (2004). [CrossRef]
5. C. Xie, C. Mu, J. R. Cox, and J. M. Gerton, "Tip-enhanced fluorescence microscopy of high-density samples," Appl. Phys. Lett. 89, 143117 (2006). [CrossRef]
6. H. F. Hamann, M. Kuno, A. Gallagher, and D. J. Nesbitt, "Molecular fluorescence in the vicinity of a nanoscopic probe," J. Chem. Phys. 114, 8596-8609 (2001). [CrossRef]
7. A. Hartschuh, E. J. Snchez, X. S. Xie, and L. Novotny, "High-Resolution Near-Field Raman Microscopy of Single-Walled Carbon Nanotubes," Phys. Rev. Lett. 90, 095503 (2003). [CrossRef]
8. V. V. Protasenko, M. Kuno, A. Gallagher, and D. J. Nesbitt, "Fluorescence of single ZnS overcoated CdSe quantum dots studied by apertureless near-field scanning optical microscopy," Opt. Commun. 210, 11-23 (2002). [CrossRef]
9. E. J. Sanchez, L. Novotny, G. R. Holtom, and X. S. Xie, "Room-temperature fluorescence imaging and spectroscopy of single molecules by two-photon excitation," J. Phys. Chem. A 101, 7019-7023 (1997). [CrossRef]
10. E. J. Sanchez, L. Novotny, and X. S. Xie, "Near-field fluorescence microscopy based on two-photon excitation with metal tips," Phys. Rev. Lett. 82, 4014-4017 (1999). [CrossRef]
11. T. J. Yang, G. A. Lessard, and S. R. Quake, "An apertureless near-field microscope for fluorescence imaging," Appl. Phys. Lett. 76, 378-380 (2000). [CrossRef]
12. R. Hillenbrand, F. Keilmann, P. Hanarp, D. S. Sutherland, and J. Aizpurua, "Coherent imaging of nanoscale plasmon patterns with a carbon nanotube optical probe," Appl. Phys. Lett. 83, 368-370 (2003). [CrossRef]
13. L. Novotny and B. Hecht, Principles of Nano-Optics (Cambridge, 2006).
14. R. Dorn, S. Quabis, and G. Leuchs, "Sharper focus for a radially polarized light beam," Phys. Rev. Lett. 91, 233901 (2003). [CrossRef]
15. B. Knoll and F. Keilmann, "Enhanced dielectric contrast in scattering-type scanning near-field optical microscopy," Opt. Commun. 182, 321-328 (2000). [CrossRef]
16. R. Hillenbrand, B. Knoll, and F. Keilmann, "Pure optical contrast in scattering-type scanning near-field microscopy," J. Microsc  202, 77-83 (2000). [CrossRef]
17. P. G. Gucciardi, G. Bachelier, and M. Allegrini, "Far-field background suppression in tip-modulated apertureless near-field optical microscopy," J. Appl. Phys. 99, 124309 (2006). [CrossRef]
18. F. Keilmann and R. Hillenbrand, "Near-field microscopy by elastic light scattering from a tip," Phil. Trans. R. Soc. London, Ser. A 362, 787-805 (2004). [CrossRef]
19. J. W. Strutt, "On the resultant of a large number of vibrations of the same pitch and of Arbitrary Phase," Philos. Mag. X, 73-78 (1880).

Author Affiliations

Jordan M. Gerton

University of Utah

Benjamin D. Mangum, Chun Mu

University of Utah, Department of Physics

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