Point spread function and lateral resolution analysis of digital holographic microscopy system

A major issue so far for digital holography is the low lateral resolution. In order to improve the resolution, we deduce the point spread function of the most common and practical digital holographic microscopy system. Based on the derived formulas, the determinant factor of lateral resolution of the system is analyzed. The results show that the optimal resolution of this system is limited by the numerical aperture of microscope objective, and the resolution can be further deteriorated by the recording media parameters and recording distance. By decreasing the recording distance the resolution can be improved dramatically. In addition, by choosing large photosensitive area and small pixel size camera the resolution of the holographic microscopy system can be improved a little. Moreover, the highest resolution and the best image quality can be achieved by image-plane digital holography. Experiment results demonstrate the correctness of the theoretical analysis.