Two-photon excitation in scattering media by spatiotemporally shaped beams and their application in optogenetic stimulation

Aurélien Bègue , Eirini Papagiakoumou (1) , Ben Leshem , Rossella Conti , Leona Enke , Dan Oron (2) , Valentina Emiliani (1)

1 UMR 8250 - Laboratoire de Neurophotonique
2 Department of Physics of Complex Systems

The use of wavefront shaping to generate extended optical excitation patterns which are confined to a predetermined volume has become commonplace on various microscopy applications. For multiphoton excitation, three-dimensional confinement can be achieved by combining the technique of temporal focusing of ultra-short pulses with different approaches for lateral light shaping, including computer generated holography or generalized phase contrast. Here we present a theoretical and experimental study on the effect of scattering on the propagation of holographic beams with and without temporal focusing. Results from fixed and acute cortical slices show that temporally focused spatial patterns are extremely robust against the effects of scattering and this permits their three-dimensionally confined excitation for depths more than 500 µm. Finally we prove the efficiency of using temporally focused holographic beams in two-photon stimulation of neurons expressing the red-shifted optogenetic channel C1V1.

Domaines: Physique [physics]; Neurobiologie

Aurélien Bègue, Eirini Papagiakoumou, Ben Leshem, Rossella Conti, Leona Enke, et al.. Two-photon excitation in scattering media by spatiotemporally shaped beams and their application in optogenetic stimulation. Biomedical optics express, 2013, 4 (12), pp.2869. ⟨10.1364/boe.4.002869⟩. ⟨hal-01963726⟩