Stereo Holographic Diffraction Based Tracking of Microrobots

Three-dimensional (3-D) tracking of microrobots is demonstrated using stereo holographic projections. The method detects the lateral position of a microrobot in two orthogonal in-line holography images and triangulates to obtain the 3-D position in an observable volume of 1 cm 3 . The algorithm is capable of processing holograms at 25 Hz on a desktop computer and has an accuracy of 24.7 μm and 15.2 μm in the two independent directions and 7.3 μm in the shared direction of the two imaging planes. This is the first use of stereo holograms to track an object in real time and does not rely on the computationally expensive process of holographic reconstruction.