Real-time imaging of molecular organization by point scanning nonlinear fast polarization modulation

Abstract

Polarized nonlinear scanning imaging using two photon fluorescence, harmonic generation or coherent Raman has been extensively developed to image molecular orientational organization in tissues. Current approaches using fast modulation (electro-optic) are however still limited to seconds time scales due to their required voltage shape modulation. To reach higher frequencies, we have developed an interferometric frequency shift-based method using Acousto-Optic Modulation. We present degree-precision performances in the retrieved information even at low signal to noise level and sub-second dynamics. The method is applied to real time actin structural imaging in cells as well as collagen and lipids organization imaging in tissues.