On Thursday, November 8, 2018, Jérémy RIPORTO, PhD student in Sciences Pour l'Ingénieur at the Laboratoire des Systèmes et Matériaux pour la Mécatronique (SYMME), will defend his thesis "Réponses multiharmoniques et résonances de nanocristaux par diffusion et microscopie multiphotonique".
The defense will take place at 10am, in amphitheatre B14, at Polytech Annecy-Chambéry, on the Annecy campus.
Summary of the thesis
Harmonic nanocrystals with a non-centrosymmetric crystal structure possess interesting nonlinear optical properties, particularly for use as optical markers in biomedical imaging. The Hyper-Rayleigh scattering technique usually used to quantify the second harmonic response of nanoparticles in suspension has been extended in this work to determine the third-order nonlinear susceptibility of different nanomaterials (BiFeO3, ZnO, KNbO3 and LiNbO3). In addition, the development of an experimental set-up based on a wavelength-tunable source has enabled us to probe the second-order nonlinear optical resonances (for excitation between 700 nm and 1300 nm) of these different materials. The spectral response of WS2 nanosheets was also studied using the same system. Finally, we have demonstrated the detection of fourth harmonic signals from a single BiFeO3 nanoparticle using a multiphoton microscopy device associated with a Telecom laser source for future integration of these nanoparticles as frequency conversion elements for nanophotonics.