Analytical model of a microlens array homogenizer based on an angular spectrum diffraction method

To analyze the effects of various aspects on the outcome of a microlens array (MLA)-based homogenizer, an angular spectrum method (ASM)-based toolkit was developed for designing the MLA-based homogenizer and introduced in this study. A finer rotating diffuser model was developed to more accurately model a practical diffuser and enhance the comprehension of the temporal integral. An intuitive algorithm was used to simulate the entire temporal integration process. Experiments and simulations were conducted to verify the practicality of the toolkit. Three evaluation functions-uniformity, speckle contrast, and flatness-were used to evaluate the homogeneity of the homogenizer. The results under various conditions, including different Fresnel numbers, were analyzed. Simple standards for designing an MLA-based homogenizer were derived as a guide. This toolkit facilitates a flexible and precise homogenizer design and can also be used for other optical systems based on wavefront manipulation.