Towards the fluorescence resonance energy transfer (FRET) scanning near-field optical microscopy with chemical selectivity

Summary form only given. The spatial resolution of scanning near-field optical microscope (SNOM) is limited by the size of an aperture for the light transmission and ranges 50-100 nm, although 20 nm resolution has been demonstrated. Further improvement of the resolution seems problematic for the "classical" SNOM configurations because the number of photons "seeping" through an aperture is rapidly decreasing with the decrease of the aperture size. A number of new approaches to improve the resolution, such as SNOM using fluorescence resonant energy transfer (FRET) between a single fluorescence center of the tip and the sample studied have been proposed.