Nanometer-resolution optical probe using a metallic-nanoparticle-intercalated carbon nanotube

We propose a nanometer-resolution optical probe tip for near-field scanning optical microscopy that utilizes a carbon nanotube (CNT) with a conical bottom end, in which gold nanoparticles are intercalated. The near-field component of the input source was coupled with a nanoparticle at the top end of the CNT and was plasmonically transferred through both the CNT and nanoparticles to reproduce a nanometer-order near-field spot at the bottom end of the CNT. The field distribution at the output plane of the CNT probe tip was calculated using the finite-difference time-domain algorithm; a 5 nm near-field optical spot was obtained at a wavelength of 886 nm for a 20 nm diameter and 200 nm long CNT probe tip filled with 4 nm diameter gold nanoparticles. The spectral response of the CNT probe tip was also presented. These results indicate that a metallic-nanostructure-intercalated CNT probe tip has significant potential for nanometer-resolution optical imaging.