Nanoscale Fluorescence Microscopy Using Carbon Nanotubes

We demonstrate the first reported use of single-walled carbon nanotubes as nano-optical probes in apertureless near-field fluorescence microscopy. We show that, in contrast to silicon probes, carbon nanotubes always cause strong fluorescence quenching when used to image dye-doped polystyrene spheres and Cd-Se quantum dots. For quantum dots, the carbon nanotubes induce very strong near-field contrast with a spatial resolution of 20 nm. Images of dye-doped spheres exhibit crescent-shaped artifacts caused by distortions in the surface water layer found in ambient conditions.