Raman resonance and orientational order in fibers of single-wall carbon nanotubes

Polarized Raman spectroscopy is used to study Raman resonance and orientational order in fibers of single-wall carbon nanotubes. The polarized Raman intensity follows essentially the same angle dependence for both radial breathing mode and tangential modes and for both semiconducting and metallic nanotubes. A simple resonant model is proposed, which provides good fits of the whole vertical-vertical and vertical-horizontal data in different kinds of fibers. The model is used to describe orientational order of nanotubes in anisotropic fibers.