Experiments in nonlinear nanophotonics combine inverted optical microscope, local-probe microscopes, femtosecond laser excitations and various detection systems.
Nonlinear nanophotonics deals with nonlinear optical properties of nano-objects. When a medium is subjected to a sufficiently intense light beam, obtained by spatial and temporal localization of the electromagnetic fields, the polarization created by the light wave is no more limited to the linear response but should be developed in the form of a series of terms in powers of the incident field. Thus, new processes appear, such as the generation of light at multiple frequencies of the incident light frequency.
Our team is particularly interested in second harmonic generation by nano-objects, as well as multiphoton-excited fluorescence. The main target applications are the development of nano-sources of light and nano-lasers.
Nano-objects that we are studying are essentially nanostructures of noble metals (such as colloidal gold nanoparticles), associated with organic luminophores. The main objective is to make the most of the excitation of surface plasmons, the latter being at the origin of strong local enhancements of electromagnetic fields in the close vicinity of the nanoparticle.
In order to directly correlate the presence of an individual nano-object with its specific optical properties (intensity, pattern , emission spectrum ... ), specially designed characterization experiments have been developed. They combine inverted optical microscope, local-probe microscopes, femtosecond laser excitations and various detection systems.
Contact : Céline Fiorini-Debuisschert