The optimization criteria for resolution improvement in a lens-free on-chip digital holographic microscope

Abstract

The typical lens-free on-chip digital holographic microscopy (LFOCDHM) as a modern imaging technique produce compromised imaging resolution that far below the ideal coherent diffraction limit. At least five major factors may contribute to this limitation, namely, the sample-to-sensor distance, spatial and temporal coherence of the illumination, finite pixel size of the sensor, and finite extent of the image sub-field-of-view used for the reconstruction. In this paper, we derive five transfer function models that account for all these physical effects on the imaging resolution of LFOCDHM. The theoretical resolution limit of a given LFOCDHM system can also be predicted. Besides this, we provide a useful guide to the selection of different system parameters for the optimization of the imaging resolution when designing a new LFOCDHM system.