Analyzing performance fluctuations in flat lenses due to feature structure distortion using a novel differential profile parsing method

Multi-level diffractive lenses (MDLs), known for their remarkable broadband achromatic properties, emerge as a popular research topic for lightweight optical systems. As advancements in the optimization design framework continue, the distortion of the MDL feature structure (ring-bands) caused by manufacturing accuracy becomes a critical factor restricting their practical application. This research refines the functional relationships associated with the MDL feature structure and presents an innovative analytical method based on differential profile parsing (DPP) to efficiently and accurately investigate the performance loss caused by the distortion of the MDL feature structure. As a result, investigations into lens performance loss are undertaken for seven types of distortions in three categories, which arise from several typical MDL manufacturing processes. By using the DPP method, this study provides insights into the manufacturing tolerances of the MDL and general recommendations for process optimization. The final optical characterization largely verifies that the proposed theory provides valuable guidance in practical manufacturing applications, illustrating that reducing the distortion degree of the MDL feature structure dramatically improves MDL optical performance.