Coherent anti-Stokes Raman scattering as an effective tool for visualization of single-wall carbon nanotubes

Strong vibrational coherent anti-Stokes Raman scattering (CARS) signal was observed in single-wall carbon nanotubes (SWCNTs) having three different average diameters (about 0.8 nm, 1.1 nm and 1.3 nm) under optical excitation close to electronic resonance energies of nanotubes. By varying the excitation power from 1 up to 200 µW an optimal regime for non-destructive investigation of nonlinear properties of SWCNTs was determined. The possibility to detect a strong coherent nonlinear signal from small SWCNT-bundles together with CARS advantages over Raman scattering, such as high imaging rate, open new opportunities for fast three-dimensional visualisation of SWCNTs in a polymer matrix.