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Nonlinear microscopy

Within the nanobiophotonic platform of IdA, research in nanophotonics serves a broad community, from physics to material sciences and life sciences. Its emphasis is on nonlinear  imaging microscopy  based on constantly upgraded versions of polarization resolved confocal biphotonic microscopy.
Applications are in elaboration and characterization of:
  • advanced nonlinear plasmonic structures, including chiral properties
  • Investigation of ferroelectric structures.
  • Imaging of cellular structures and biological tissues

The nonlinear microscopy platform is devoted to polarization resolved multiphoton microscopy, comprising : an inverted Nikon microscope, a Mai-Tai tunable femtosecond laser (Spectra Physics) pumping an Opal Optical Parametric Oscillator. This set-up allows to prove in a quantitative way, down to individual nanosctructures, a broad range of samples, via their second and third harmonic generation properties, as well as their two photon fluorescence. It is complementary to the electrooptic interferometric microscope which is exploiting the electrooptic properties of samples. This combination is unique to our group with the potential to explore in depth the nonlinear properties of nanostructures of interest. The polarization resolution that if offers allows to retrieve the nonlinear tensor coefficients associated to various nonlinear processes, also as to provide information on the higher order anisotropy of the nonlinear response of nanostructures.

Together with  Hoang Minh Ngo, Joseph Zyss and Isabelle Ledoux, we investigate the  SHG properties of gold nanostructures with tailored triangular structure, as from colloïdal soft synthesis, which exhibit record high quadratic efficiency.  The longer term goal is to transfer angular momentum from light to these structures via nonlinear processes.

Together with the CNR in Napoli-Pozzuoli, arrays of gold nano-triangles from top down electron beam methods, that feature chiral properties so as to evidence a high nonlinear contrast, allowing to discriminate left and right handed nanostructures, with possible applications to water-marking and encryption techniques.

Together with the Weizmann Institute (within the associated CNRS-Weizmann Laboratory « NaBi »), we aim at elaborating and investigating 3-D nonlinear nanoplasmonic structures, where one could further enhance chiral discrimination making use of the z-axial helicity resulting from the twisted piling-up of successive layers.
Both projects are aiming at the control of the helicity of light at the nanoscale, so as to promote nonlinear chiral imaging and recognition techniques of major interest for biological applications.

Recent achievements :

Periodic bidimensional array of nonlinear plasmonic nanostructures displaying an highly anisotropic nonlinear response further enhanced by meta-crystalline cooperativity. (in collaboration with EPFL in Lausanne)

Chiral discrimination by SHG from a circularly polarized fundamental beam, of left- and right handside arrangements of triangular gold nano-particles. This effect is used to encode a pattern (here the R letter) by motives of a given handedness while the background is made of the opposite one.

Available  equipements :


- Laser Mai Tai Spectra-Physics tunability : 690  to 1040 nm
- OPO Opal Spectra-Physics, 1.1 to 1.3µm
- Inverted Nikon Microscope
- Photon counting detectors
- Spectrometer

Localisation :

Bât. IDA (Pièce B35)