Spatiotemporal heterodyne detection

Abstract

We describe a scheme in which a camera is turned into an efficient tunable frequency filter of a few-Hertz bandwidth in an off-axis, heterodyne optical mixing configuration, enabling one to perform parallel, high-resolution coherent spectral imaging. This approach is made possible through the combination of a spatial and temporal modulation of the signal to reject noise contributions. Experimental data obtained with dynamically scattered light by a suspension of particles in Brownian motion is interpreted.