Nano-slit probes for near-field optical microscopy fabricated by focused ion beams

The near-field probes described in this paper are based on metallized non-c ontact atomic force microscope cantilevers made of silicon. For application in high-resolution near-field optical/infrared microscopy, we use aperture probes with the aperture being fabricated by focused ion beams. This techn ique allows us to create apertures of sub-wavelength dimensions with differ ent geometries. In this paper we present the use of slit-shaped apertures w hich show a polarization-dependent transmission efficiency and a lateral re solution of < 100 nm at a wavelength of 1064 nm. As a test sample to charac terize the near-field probes we investigated gold/palladium structures, dep osited on an ultrathin chromium sublayer on a silicon wafer, in constant-he ight mode.