Special multicolor illumination and numerical tilt correction in volumetric digital holographic microscopy

We introduce a color imaging method in our digital holographic microscope system (DHM). This DHM can create color images of freely floating, or moving objects inside a large volume by simultaneously capturing three holograms using three different illumination wavelengths. In this DHM a new light source assembly is applied, where we use single mode fibers according to the corresponding wavelengths that are tightly and randomly arranged into a small array in a single FC/PC connector. This design has significant advantages over the earlier approaches, where all the used illuminations are coupled in the same fiber. It avoids the coupling losses and provides a cost effective, compact solution for multicolor coherent illumination. We explain how to determine and correct the different fiber end positions caused tilt aberration during the hologram reconstruction process. To demonstrate the performance of the device, color hologram reconstructions are presented that can achieve at least 1 µm lateral resolution.