Three-dimensional particle localization with common-path digital holographic microscopy

In this paper, we present a common-path digital holographic microscope for 3D particle localization. Due to the common-path geometry, our setup is self-referencing, which reduces mechanical sensitivity to environmental disturbances. Thus, the system provides high stability and phase sensitivity down to 10nm. For system testing, different particles of varying size and material are distributed in a phantom material. Holograms are recorded by a camera and reconstructed with the angular spectrum method, phase unwrapping and Zernike polynomials. Numerical propagation of a single-shot hologram to multiple focal planes allow for optimal focusing on the sample. The resulting images show the different positions and distribution of particles.