Nonlinear optical properties of single-wall carbon nanotubes and organic nanohybrids: enhancement through double resonance, coherent addition and symmetry breaking.

Organic nonlinear optics (NLO) deals with the nonlinear response of organic molecular materials exposed to intense light beams, with prospective applications in optical telecommunication based on ultrafast switches and modulators, and highly efficient frequency convertors. In this research project, novel approaches will be examined to significantly amplify the molecular NLO response, in particular: (i) doubly (one- and twophoton) resonant enhancement, (ii) coherent addition of contributions from multiple molecular units and (iii) symmetry-breaking in formally centrosymmetric yet bistable molecules. To this aim, the NLO response of different molecular systems will be directly determined through ultrasensitive wavelength-dependent hyper-Rayleigh scattering (HRS) experiments in the appropriate wavelength ranges, using the setup I developed recently and which is unique in terms of both sensitivity and spectral tuneability. Measurements will be performed on well-designed organic molecules, as well as on single-wall carbon nanotubes (SWNTs), both empty and filled with efficient NLO chromophores. For the empty SWNTs,not only the second-order NLO response, but also the third-order response will be characterised by HRS at the tripled frequency. Finally, low-symmetry radial vibrational modes, never observed before but theoretically expected to be highly dependent on tubediameter and environmental interactions (e.g. filling), will be accessible by ultrasensitive (second- and third-order) hyper-Raman experiments.

Keywords:CARBON NANOTUBE, NON-LINEAR OPTICAL MATERIALS

Disciplines:Astronomy and space sciences, Condensed matter physics and nanophysics

Project type:Collaboration project