Resonance Raman Spectra of Carbon Nanotubes by Cross-Polarized Light

Resonance Raman studies on single wall carbon nanotubes (SWNTs) show that resonance with cross polarized light, i.e., with the $E_{\mu ,\mu \pm 1}$ van Hove singularities in the joint density of states needs to be taken into account when analyzing the Raman and optical absorption spectra from isolated SWNTs. This study is performed by analyzing the polarization, laser energy, and diameter dependence of two Raman features, the tangential modes ($G$ band) and a second-order mode ($G^{\prime }$ band), at the isolated SWNT level.