Multiwalled　carbon　nanotubes　(MWCNTs)　were　individually　coated　with　conducting,　semiconducting,　and　insulating　materials.　The　coatings　used　were　crystalline　Au　nanoparticles,　TiO2　nanoclusters,　and　amorphous　SiO2　nanoshells,　respectively.　The　synthesis　strategy　involves　a　combination　of　self-assembly　and　the　sol-gel　technique.　The　synthesized　nanostructures　were　characterized　by　transmission　electron　microscopy,　energy-dispersive　Xray　spectroscopy,　Raman　spectroscopy,　and　X-ray　diffraction.　We　investigated　the　nonlinear　optical　and　optical　limiting　properties　using　an　open-aperture　Z-scan　technique　and　fluence-dependent　transmittance　measurements.　Compared　to　the　pristine　MWCNTs,　those　with　Au-,　TiO2-,　and　SiO2-coatings　demonstrate　superior,　equivalent,　and　inferior　nonlinear　optical　and　optical　limiting　properties,　respectively.　(C)　2010　Elsevier　Ltd.　All　rights　reserved.