Lens-free inline holographic microscopy with numerical correction of layers with different refractive index

Digital inline holographic microscopy is applied for lens-free imaging with high lateral resolution. Microfluidic chambers for imaging of cells in water-like or native solutions, e.g. thick layers of glass and other materials with different refractive index, cause aberrations which limit the spatial resolution and change the magnification scale. In the paper, a fast reconstruction technique considering parallel layer systems of different refractive indices is presented. In experiments, properly scaled images of micro-beads and red human blood cells with an optical resolution corresponding to a numerical aperture of about 0.62 were reconstructed.