We present fluorescence resonance energy transfer (FRET) images of donor dye molecule clusters recorded using a local fluorescence probe for scanning near-field optical microscopy (SNOM): standard apertured SNOM fiber tip coated with the 30-100-nm-thick polymer layer stained with the acceptor dye molecules. The tip works as a "self-sharpening pencil": the apical layers of the FRET-active tip coating are mechanically worn out during scanning thus continuously exposing a fresh active apex to continue imaging. Only a few tens of acceptor molecules are used to form the optical images, and using such an approach spatial resolution better than the size of the aperture is achievable.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)