A general model for resolution of digital holographic microscopy

For digital holographic microscopic imaging, the resolution in the reconstructed image is one of the most important parameters. To optimize the lateral resolution, a general model for the resolution of digital holographic microscopy (DHM) is proposed in this work, in which the effects of the sizes of each pixel, total area of the charge coupled device (CCD) and the microscopic objective lens are taken into account. Comparison between our model and others was carried out by calculating the point spread function (PSF) of DHM at different reconstruction distances and with different fill factors. It is shown that the effect of fill factors on the resolution of DHM becomes significant when the reconstruction distance is long. For high resolution DHM imaging the influence of fill factors must be taken into account when estimating the resolution of the reconstructed image. Furthermore, It is also demonstrated that the sidelobe of PSF can be cut effectively choosing appropriate values of the fill factors. Finally, the reconstructions of polyethylene microspheres have been implemented to demonstrate the theoretical analysis. These results obtained are helpful for estimation of the resolution and design of the DHM systems.