Experimental evidence of localized plasmon resonance in composite materials containing single-wall carbon nanotubes

Experimental proof of localized plasmon resonance was found in thin films containing either single-walled carbon nanotubes (SWNT) or SWNT bundles of different length. All samples were prepared by a simple technique that permitted the selection of different SWNT lengths in different samples without significant differences in electronic properties. Fourier-transform infrared spectroscopy showed that an optical-density peak, the same as a terahertz conductivity peak, shifts to higher frequencies as the SWNT lengths are reduced---in agreement with a similar tendency predicted for the localized plasmon resonance in finite-length SWNTs [Slepyan et al., Phys. Rev. B 81, 205423 (2010)].