Local fluorescence probes based on CdSe semiconductor
nanocrystals were prepared and tested by recording scanning
near-field optical microscopy (SNOM) images of calibration
samples and fluorescence resonance energy transfer SNOM
(FRET SNOM) images of acceptor dye molecules inhomogeneously
deposited onto a glass substrate. Thousands of nanocrystals
contribute to the signal when this probe is used as a
local fluorescence source while only tens of those (the most
apical) are involved in imaging for the FRET SNOM operation
mode. The dip-coating method used to make the probe enables
diminishing the number of active fluorescent nanocrystals
easily. Prospects to realize FRET SNOM based on a single fluorescence
centre using such an approach are briefly described.