High-space-bandwidth product characterization of metalenses with Fourier ptychographic microscopy

TL;DR

This paper introduces a Fourier ptychographic microscopy technique for high space-bandwidth product characterization of metalenses, enabling detailed phase measurement over large apertures with high resolution.

Contribution

The paper presents a novel high SBP phase characterization method for metalenses using Fourier ptychographic microscopy, addressing previous measurement limitations.

Findings

Achieved 4.91 MP high SBP measurement of metalenses

Quantified fabrication errors' effects on optical performance

Provided targeted aberration compensation strategies

Abstract

Large numerical aperture (NA) and large aperture metalenses have shown significant performance and abundant applications in biomedical and astronomical imaging fields. However, the high space-bandwidth product (SBP) requirements for measuring the phase of these metalenses, characterized by small phase periods and large apertures, have resulted in no effective techniques for sufficient characterization. In this paper, we propose a high SBP phase characterization technique using Fourier ptychographic microscopy (FPM), enabling a high spatial resolution and wide field of view simultaneously. To demonstrate the feasibility and effectiveness of this technique, we achieve a high SBP (4.91 megapixels) measurement and characterization for focusing and focusing vortex metalenses, quantitatively displaying the effect of fabrication error on their typical optical performance. Furthermore, we characterize the aberration type and amount of wavefront deviations caused by fabrication. We also analyze compensation methods for different aberrations based on the wavefront characterization results, providing a targeted alignment strategy for optimizing overall optical system performance. We believe that our high SBP characterization technique cannot only help to improve metalens design but also optimize its fabrication processing, which will pave the way for the diversified applications of metalenses.