Optimization of Hybrid Optics with Multilevel Phase Mask for Improved Depth of Focus Broadband Imaging

This paper is devoted to designing of hybrid refractive/diffractive optics for high-quality imaging with improved depth of focus (DoF). The novelty of the concept is in sharing of the optical power of the refractive lens between the lens and a multilevel phase mask (MLM) as a diffractive optical element (DOE). The efficiency of the design is confirmed by numerical results. Broadband multiwavelength test-images are exploited for the design and testing of the system. It is shown that the obtained hybrid optical system in combination with computational inverse imaging provides both a better image quality (due to the robustness of the designed optics to chromatic aberrations) and an extended depth of focus as compared with the refractive lens and the diffractive lensless design with MLM.