Distance and orientation measurement in the nanometric scale based on polarization anisotropy of metallic dimers.

We show that the orientation of a dimer and the distance between the nanoparticles that form it can be determined by measuring the scattering under polarized light illumination. Scattering microscopy has shown to be an alternative to fluorescence as it provides nonbleaching and highly biocompatible probes, that can be manufactured in different sizes with different ligands. We propose a method based on measuring the polarization anisotropy of metallic dimers to determine distances in the range from 10 nm to 200 nm, thus filling the gap between fluorescence resonance energy transfer (FRET) and conventional microscopy. By calculating the scattering cross section of metallic dimers we show that it is also possible to gather orientation information, relevant to understand many biological processes.