Optical waveguide through CdS nanoribbons

The synthesis of CdS nanoribbons by the physical evaporation of a CdS nanopowder in presence of a Au catalyst, and the waveguide properties of these nanoribbons. are discussed. The guided band-edge luminescence through individual CdS nanoribbons were detected by imaging the spatially localized photoluminescence (PL) intensity and simultaneously recording the PL spectra at different traveling distances using near-field scanning optical microscopy (NSOM). The ribbons were pumped with a tightly focused laser beams at different local position along various length relative to a NSOM collection tip held stationary over one of their ends. It was found that that the locally produced band-edge photoluminescence can be effectively transported several hundred micrometers away along a single CdS nanoribbon, and the emission bands show a significant red-shift with respect to increasing traveling distances.