Fabrication of a near-field optical fiber probe with a nanometric metallized protrusion

We have developed a novel probe with a nanometric metallized protrusion ext ending through a subwavelength aperture to increase optical near-field exci tation and collection efficiencies. The apex diameter of the fabricated met allized protrusion was 35 nm. The Intensity distribution of the optical nea r-field at the apex of the probe was measured by scanning another probe acr oss the apex, and it was observed that strong optical near-field was genera ted at the apex of the metallized protrusion. The width of the intensity di stribution was 150 nm including instrumental resolution. Probes with spheri cal and ellipsoidal metallized protrusion were also fabricated, by which en hancement of the optical near-field is expected due to localized plasmon ex citation.