Interferometric laser measurement of multi-axial mechanical properties exhibited by carbon nanotubes

Interferometric optical experiments for measuring changes in fringe irradiance patterns dependent on optical and mechanical responses associated to carbon nanotubes are reported. Thin solid films conformed by multiwall carbon nanotubes were prepared by an aerosol pyrolysis method. A Michelson optical interferometer with a highly stable 488 nm wavelength was employed for evaluating the studied sample. According to the interferometric results, the strain of the carbon nanotubes presented a nonlinear behavior resulting from applied multiaxial forces. On the other hand, for further investigating the effect of the variation of the mechanical properties and the optical characteristics of the tubes, nonlinear optical experiments were performed when the sample was exposed to a mechanical action. The third order nonlinear optical response was explored with the assistance of the second harmonic provided by a Nd:YAG laser system in a two-wave mixing configuration. Potential applications for mechano-optical modulation by nanosystems based on carbon nanotubes are contemplated.