True-color real-time imaging and spectroscopy of carbon nanotubes on substrates using enhanced Rayleigh scattering

Single-walled carbon nanotubes (SWCNTs) illuminated by white light should appear colored due to resonance Rayleigh scattering. However, true-color imaging of SWCNTs on substrates has not been reported, because of the extremely low scattering intensity of SWCNTs and the strong substrate scattering. Here we show that Rayleigh scattering can be greatly enhanced by the interface dipole enhancement effect. Consequently colorful SWCNTs on substrates can be directly imaged under an optical microscope by wide field supercontinuum laser illumination, which facilitates high throughput chirality assignment of individual SWCNTs. This approach, termed Rayleigh imaging microscopy, is not restricted to SWCNTs, but widely applicable to a variety of nanomaterials, which enables the colorful nanoworld to be explored under optical microscopes.