Lens less inline holographic microscope for blood cell imaging

A digital inline holographic microscope consisting of a laser diode, a microfluidic chip and a CCD image sensor is used for lens less imaging of human blood cells. A microscope-demonstrator for blood cell counting is presented. A pinhole which acts as a partial coherent point source is integrated in the microfluidic chip. Samples of diluted full blood as well as isolated white blood cells flowing through the channel of the microfluidic chip were imaged. Holograms are taken at video rate where each hologram is used to reconstruct a set of images of the whole volume of the fluidic channel (3D imaging). The holographic phase-contrast images are used for identification of the cells. A spatial resolution of about 1 µm is reached by applying a self-calibration technique for determination of the reference wave front using micro structured markers. Videos of flowing different cells are shown.