Design of diffractive microlenses using general focal length function

摘要

In order to study the validity of general focal length function in designing diffractive microlenses with long focal depth, diffractive microlenses with different f-numbers are designed using general focal length function and their focusing characteristics, such as real focal depth, real focal spot size, and diffractive efficiency, are investigated using electromagnetic theory and boundary element method. Investigation results indicate that general focal length function can be used to achieve long focal depth in designing diffractive microlenses, even twice over than those of conventional diffractive microlenses with similar parameters.