3 dimension 3 coordinate velocity measurements of electrothermal vortex using Interference micro Particle Tracking Velocimetry

We present velocity measurements of an electrothermal vortex using Interference micro Particle Tracking Velocimetry (I-$\mu$PTV). These measurements are compared to results obtained using Astigmatism micro-Particle Tracking Velocimetry (A-$\mu$PTV). We will also demonstrate several of the advantages of this system such as an increased measurement volume thickness as well as the ability to use small particles ($<$ 1 $\mu$m diameter).