ENP alumnus Aurélien Bègue, now a postdoc at Harvard Medical School, contributed to several publications during his PhD. Recently, he and his colleagues focused on the distortion of light that occurs when it passes through brain tissue and how this distortion can be robustly compensated in order to achieve efficient two-photon excitation of optogenetic molecules. The team used temporally focused two-photon excitation and generalized phase contrast on brain slices. They found three-dimensional illumination patterns  remained confined and led to efficient photoexcitation more than 200 micrometers deep. The study was also extended to another beam shaping technique called Digital Holography in another publication. Get more details in the articles:

Papagiakoumou E*, Anselmi F*, Bègue A*, de Sars V, Glückstad J, Isacoff EY, Emiliani V.Scanless two-photon excitation of channelrhodopsin-2. Nature Methods. 2010. 7: 848–854.

Papagiakoumou E, Bègue A, Leshem B, Schwartz O, Stell BM, Bradley J, Oron D, Emiliani V. Functional patterned multiphoton excitation deep inside scattering tissue. Nature Photonics. 2013. 7: 274-278. 

Bègue A, Papagiakoumou E, Leshem B, Conti R, Enke L, Oron D, Emiliani V. Two-photon excitation in scattering media by spatiotemporally shaped beams and their application in optogenetic stimulation. Biomedical Optics Express. 2013. 4(12): 2869-2879.

Keywords:Biophotonics, Imaging and sensing, Two-photon, Photoexcitation

Figure 6 from Bègue et al., Biomed Op Express, 2013. Figure shows how an ultrafast line scanning of the sample can be produced by propagation of a large beam that is diffracted by a grating.

Aurélien received the Prix jeunes chercheurs 2013 of the Fondation Bettencourt Schueller.