The extended depth of field microscope imaging system with the phase pupil mask

A ‘0/π’ phase pupil mask was developed to extend the depth of field of a circularly symmetric optical microscope imaging system. The modulation transfer function curves, the normalized point spread function figures and the spot diagrams of the imaging system with the optimal mask were analyzed and simulated. The results show that the large depth of field imaging system with the ‘0/π’ phase pupil mask has a high resolution in a long frequency band and can obtain clear images without any post-processing. The experimental results also demonstrate that the depth of field of the imaging system is extended successfully.