Anisotropic optical properties of vertically aligned single-walled carbon nanotubes

Regular reflectance measurements of a forest of vertically aligned single-walled carbon nanotubes were made as a function of an incident angle for the S- and P-polarized lights in the infrared region. The low reflectance measured at normal incidence, 0.0005-0.0009, supports a model of a low material density and also the incident angle dependence of reflectance spectra for the S- and P-polarized lights suggests that the single-walled carbon nanotubes are highly anisotropic materials. These reflectance data, used in conjunction with an analysis of the Fresnel relations for anisotropic materials, permit optical constants to be obtained both parallel and perpendicular to the surface.