Reflection scanning near-field optical microscopy with uncoated fiber tips: How good is the resolution really?

We have investigated the optical resolution of a scanning near-field optical microscope in reflection collection mode using an uncoated fiber tip. We demonstrate that the apparent resolution in the optical signal (better than 70 nm) is a topography-induced effect. We believe that the purely optical resolution is only of the order of lambda/2 and diffraction limited. (C) 1997 American Institute of Physics