[OPTICAL REVIEW Vol. 5, No. 6 (1998) 369-373]

Fabrication of a Near-Field Optical Fiber Probe with a Nanometric Metallized Protrusion

Takuya MATSUMOTO,1 Tsutomu ICHIMURA,1 Takashi YATSUI,1 Motonobu KOUROGI,1 Toshiharu SAIKI2 and Motoichi OHTSU1,2

1Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259, Nagatsuta, Midori-ku, Yokohama, 226-8502 Japan, 2Kanagawa Academy of Science and Technology, KSP East 408, 3-2-1, Sakado, Takatsu-ku, Kawasaki, 213-0012 Japan

(Received June 26, 1998; Accepted August 21, 1998)

We have developed a novel probe with a nanometric metallized protrusion extending through a subwavelength aperture to increase optical near-field excitation and collection efficiencies. The apex diameter of the fabricated metallized protrusion was 35 nm. The Intensity distribution of the optical near-field at the apex of the probe was measured by scanning another probe across the apex, and it was observed that strong optical near-field was generated at the apex of the metallized protrusion. The width of the intensity distribution was 150 nm including instrumental resolution. Probes with spherical and ellipsoidal metallized protrusion were also fabricated, by which enhancement of the optical near-field is expected due to localized plasmon excitation.

Key words : near field optical microscope, fiber probe, metallized protrusion, subwavelength aperture, localized plasmon