Theoretical and experimental characterization of fully metal coated scanning near-field optical microscopy SiO/sub 2/ tips

In spite of the considerable progress achieved in fabricating scanning near-field optical microscopy (SNOM) probes, the process to prepare smooth tip surfaces with aperture sizes under 100 nm is still expensive and time consuming. Recently, silicon cantilever-based SNOM probes with aluminum-coated quartz (fused silica) tips have been batch fabricated using micro machining technology. The tip apex is fully covered with a metal layer in the range of 60 nm thickness. It is the objective of this work to theoretically and experimentally elucidate the mechanism responsible for the light transmission through these novel probes.