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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 16, Iss. 9 — Apr. 28, 2008
  • pp: 6183–6193

Resolving single fluorophores within dense ensembles: contrast limits of tip-enhanced fluorescence microscopy

Benjamin D. Mangum, Chun Mu, and Jordan M. Gerton  »View Author Affiliations

Optics Express, Vol. 16, Issue 9, pp. 6183-6193 (2008)

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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

OCIS Codes
(180.2520) Microscopy : Fluorescence microscopy
(180.5810) Microscopy : Scanning microscopy
(180.4243) Microscopy : Near-field microscopy

ToC Category:

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

Virtual Issues
Vol. 3, Iss. 5 Virtual Journal for Biomedical Optics

Benjamin D. Mangum, Chun Mu, and Jordan M. Gerton, "Resolving single fluorophores within dense ensembles: contrast limits of tip-enhanced fluorescence microscopy," Opt. Express 16, 6183-6193 (2008)

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