Abstract
Multiwalled carbon nanotubes (MWCNTs) are seen to possess exceptional electronic and optical properties, and might allow the development of photonic devices based on their collective modes. MWCNTs would thus represent an exciting medium for use in nanocomposites. In this article, the transmission and attenuation of an E-field coupled to a surface plasmon mode, through the walls of double-walled and MWCNTs, is investigated and examined within the context of optical field enhancement. The surface mode under investigation originates from silver filling of the nanotubes. Highly spatially resolved electron energy-loss spectroscopy is used to estimate the silver Mie-plasmon transmission coefficient, which dictates the sensing volume of the silver filling. The eigenfrequency of this mode is also examined, with regards to possible hybridisation of the Mie- and the graphitic pi-surface plasmon. While a change in the Mie- plasmon energy could not be observed, the graphitic pi-surface plasmon exhibited an unusual red-shift. It appears that variation of the nanotube aspect ratio and thus of the filling diameter would allow engineering of the sensing volume, and to some degree, of the graphitic pi-surface plasmon eigenfrequency.