On Thursday, November 8, 2018, Jérémy RIPORTO, a doctoral student in Engineering Sciences at the Laboratory of Systems and Materials for Mechatronics (SYMME), will defend his dissertation titled “Multiharmonic Responses and Resonances of Nanocrystals via Multiphoton Scattering and Microscopy.”
The defense will take place at 10 a.m. in Lecture Hall B14 at Polytech Annecy-Chambéry, on the Annecy campus.
Thesis summary
Harmonic nanocrystals with non-centrosymmetric crystal structures possess interesting nonlinear optical properties, particularly for use as optical markers in biomedical imaging. The Hyper-Rayleigh scattering technique, typically 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 various nanomaterials (BiFeO3, ZnO, KNbO3, and LiNbO3). Furthermore, the development of an experimental setup based on a wavelength-tunable source enabled the investigation of second-order nonlinear optical resonances (for excitation wavelengths between 700 nm and 1300 nm) in these various materials. The spectral response of WS₂ nanosheets was also studied using the same system. Finally, we demonstrated the detection of fourth-harmonic signals from a single BiFeO3 nanoparticle using a multiphoton microscopy setup coupled with a telecom laser source, with a view to the future integration of these nanoparticles as frequency conversion elements for nanophotonics.