Design of diffractive microlenses using general focal length function

摘要

In order to study the validity of general focal length function in designing di.ractive microlenses with long focal depth, di.ractive microlenses with di.erent f-numbers are designed using general focal length function and their focusing characteristics, such as real focal depth, real focal spot size, and di.ractive e.ciency, 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 di.ractive microlenses, even twice over than those of conventional di.ractive microlenses with similar parameters.