High-Resolution Imaging of Single Fluorescent Molecules with the Optical Near-Field of a Metal Tip

Abstract

We show that a concentration of light at a metal tip allows near-field optical imaging of single fluorescent dye molecules at very high resolution, despite strong quenching effects. Details as small as 10 nm were observed in the fluorescence patterns of single Cy-3 dyes bound to the termini of DNA. Data evaluation by model fitting determines the positions of the dyes to an accuracy even better than 1 nm and also yields their 3D orientation. The metal tip simultaneously provides high-resolution topographic imaging complementing the optical signal for a detailed surface examination.

Review of near-field optics and superlenses for sub-diffraction-limited nano-imaging

“…8,11,112,[118][119][120][121][122][123] Metallic tips are usually preferred due to their more favorable scattering, confinement, and field enhancement characteristics. 14,105,116,123,124 Some study in the past decade however has shown that silicon tips are a promising solution for achieving the highest resolution with apertureless SNOM due to more capable semiconductor fabrication techniques. 113,125 FIG.…”

Nanoparticles On A String – Fiber Probes as "Invisible" Positioners for Nanostructures

“…For single particles, the enhanced near-fields are their most important property. Increasing the local intensity on a restricted volume allows for the selective excitation of single fluorescent molecules (Bharadwadj et al, 2007;Frey et al, 2004;Sandoghdar & Mlynek, 1999).…”

Antenna-Based Optical Imaging of Single Ca2+ Transmembrane Proteins in Liquids

“…To overcome these barriers, so-called "tip-enhanced near-fieldopticalmicroscopy"(TENOM)hasbeenintroduced. [24][25][26][27][28] In contrast to aperture-type NSOM, this technique is capable of achieving superior optical resolution, but the application to biological samples in physiological conditions has yet to be demonstrated. The laser-irradiated metal tip employed in TENOM can be viewed as a special type of optical antenna.…”