Design of wavefront coding microscope objective based on 4f system

Wavefront coding (WFC) technology is used to extend the depth of field in medium and high power microscope objectives. A novel WFC system is proposed here by adding a 4f system at the back of traditional objectives. Cubic phase mask (CPM), the wavefront coded element, is located in the 4f system. In this way, the cost will be cut down by maintaining the existing structure of traditional objectives. The image plane of the traditional objective should be consistent with the object plane of the 4f system. The position of CPM is determined by the focal length of 4f system and total track of the traditional objectives. Finally, One CPM is designed for both 40X and 100X objectives. Simulation results show that the depths of field for 40X and 100X microscope objectives reach 0.52mm and 0.01mm respectively, which is about 20 times and 10 times of the traditional ones.