Delphine Débarre

Use of coherent control for selective two-photon fluorescence microscopy in live organisms

We demonstrate selective fluorescence We demonstrate selective fluorescence excitation of specific molecular species in live organisms by using coherent control of two-photon excitation. We have acquired quasi-simultaneous images in live fluorescently-labeled Drosophila embryos by rapid switching between appropriate pulse shapes. Linear combinations of these images demonstrate that a high degree of fluorophore selectivity is attainable through phase-shaping. Broadband phase-shaped excitation opens up new possibilities for single-laser, multiplex, in-vivo fluorescence microscopy.

Velocimetric third-harmonic generation microscopy: micrometer-scale quantification of morphogenetic movements in unstained embryos

We demonstrate the association of third-harmonic generation (THG) microscopy and particle image velocimetry (PIV) analysis as a novel functional imaging technique for automated micrometer-scale characterization of morphogenetic movements in developing embryos. Using a combined two-photon-excited fluorescence and THG microscope, we characterize the optical properties of Drosophila embryos and show that sustained THG imaging does not perturb sensitive developmental dynamics. Velocimetric THG imaging provides a quantitative description of the dynamics of internal structures in unstained wild-type and mutant embryos.