Rotational and translational diffusion of copper oxide nanorods measured with holographic video microscopy

We use holographic video microscopy to track the three-dimensional translational and rotational diffusion of copper oxide nanorods suspended in water. Rayleigh-Sommerfeld back-propagation of a single holographic snapshot yields a volumetric reconstruction of the nanorod's optical scattering pattern, from which we estimate both its dimensions and also its instantaneous position and orientation. Analyzing a video sequence yields measurements of the freely diffusing nanorod's dynamics, from which we estimate the technique's resolution. (C) 2010 Optical Society of America