Séminaire PMMH - Gilles Tessier (Sorbonne Univ.)

Vendredi 1er juillet 11:00-12:00 - Salle réunion PMMH 1

Measuring and shaping the phase of light : new tools to study materials and biological systems

Spatially-resolved techniques to control and image the phase of light have deeply transformed microscopy. In this talk, I will briefly clarify the notion of optical phase and present two phase-sensitive techniques, both offering high sensitivity and 3D capabilities. Using holography, individual magnetic nanorods can be actuated and used as probes of the local viscosity in liquids. Using diffuser-based wavefront sensing, which is instrumentally minimal, I will show how phase can be used to measure temperature, monitor chemical reactions, and detect intrinsic movements (biological or Brownian) to reveal mechanical properties or metabolic activity.

Conversely, I will show how the optical phase can be thermally modified to obtain versatile optical functions : I will present arrays of electrically actuated lenses (illustration), or aberration correctors to improve multiplane 3D imaging, notably for in-depth optogenetic applications.