Invariant-ability of the PSF of wide-field microscopy to the DOF by using cubic phase mask

In this paper, we have suggested the new technique for the improvement of the invariant ability of the point spread function (PSF) of wide-field microscopy to the depth of field (DOF). When a cubic phase mask (CPM) is inserted in the exist-pupil position of the imaging system, the invariant-ability of the point spread function (PSF) to the DOF is enhanced. The comparison for the invariant-ability of the PSFs for the traditional imaging system (IMS) and the CPM to the DOF are presented. Moreover, the experimental setup of the IMS is built. The experimental results are shown and agree with the simulation results.