Mechano-optical modulation and optical limiting by multiwall carbon nanotubes

An optical limiting effect in multiwall carbon nanotubes was modulated by using a two-wave mixing experiment assisted with a mechanical actuator. We employed a 532 nm wavelength and 1 ns pulse duration for exciting the nonlinear optical absorption. The nanotubes were prepared by an aerosol pyrolysis method. The resulting samples were deposited on a pure silica substrate as an inhomogeneous thin film. The mechano-optical modulation was obtained by the orthogonal rotation of the sample with respect to the probe beam. In addition, low-irradiance patterns provided by a Michelson optical interferometer allowed us to comparatively corroborate the mechano-optical effect induced by the rotation of the film.