ABSTRACT
Scanning near-field optical microscopy (SNOM) is hybridized with scanning tunneling microscopy (STM) in order to extend the capability of SNOM to reveal nanoscopic optical phenomena both in the near-field region and in the proximity. The system is realized by introducing a doubly metal-coated optical fiber tip with an extremely small aperture (<100 nm), where the metal-coating of the aperture is performed to obtain a half-transparent conducting tip after the fabrication of the ‘aperture probe.’ A simultaneous SNOM/STM observation is performed for an A u (lll) surface for the purpose of showing the quality of our homemade SNOM/STM instrument, where the evanescent field standing on the tip vicinity through the aperture is scat tered by the local structures of the sample and the far-field component of the scattered light is collected as an optical signal. The distance control is carried out under constant current conditions in order to separate the optical properties from the surface topography. A/100 optical resolution and an identical channel transport for both electrons and photons are achieved. The intensity changes as a function of the gap-distance are meas ured in the far-field and near-field regions and the proximity. Possible future applications of this method to organic materials are also discussed.
