Beyond the nanometer resolution

We introduced a new optical technique that allows for versatile and efficient 3D tracking of diluted particles while offering a sub-nanometer frame-to-frame precision in all three spatial directions (Fig1). The principle is to combine stereoscopy and interferometry, such that the z (axial) position is measured through the distance between two interferometric fringe patterns (Fig2).

 

Fig1: 3D localisation of a 1µm bead.

  

   

Fig2: Two arrays of fringes created by a single bead.