Aberration retrieval for the characterization of micro-optical components

This paper proposes a method for the characterization of focusing micro-optical components such as microlens. Based on the measurement of the focal volume generated by the micro-element, the wavefront map reconstruction as well as the optical aberrations can be estimated. To record the slices of the focal volume, this technique requires a simple optical arrangement which consists of a microscope objective and a camera. Then, an iterative phase retrieval algorithm is applied on each recorded intensity slice. This approach is less sensitive to the environmental variations than interferometry and is less expensive than wavefront sampling sensors although it leads to similar results than interferometry. As an example, ball microlens with 596 mu m diameter and 0.56 numerical aperture, has been characterized and comparison with more conventional technique demonstrates the good performances of the proposed phase retrieval method.