Simultaneous determination of 3-Dimensional velocity components using a single vector beam

Laser remote sensing represents a powerful tool that enables the accurate measurement of the speed of moving targets. Crucially, most sensing techniques are 2-Dimensional in nature and do not enable direct determination of the full velocity vector of objects moving in 3D. A disadvantage that is very often compensated with two-dimensional techniques that in many cases are hard to implement and in others, require complicated post-processing analysis. Here we demonstrate a novel technique that enables the direct and simultaneous measurement of both velocity components using a single interrogating beam. This technique is based on the use of complex light beams, whose polarization and spatial degree of freedom are coupled in a non-separable way. We present experimental results of a proof-of-principle experiment by applying our technique to the specific case of helical motion, of great relevance in a wide of research areas.