近日，香港城市大学的Mu Ku Chen及其研究团队取得一项新进展。经过不懈努力，他们实现基于多距离相位检索的超透镜相位表征。相关研究成果已于2024年8月6日在国际知名学术期刊《光：科学与应用》上发表。

本文提出了一种基于光场扫描的多距离相位检索系统，并讨论了该系统的收敛性和鲁棒性。研究结果表明，只要测量噪声低，且扫描光场的总长度足够长，该系统就能够检索出超透镜的相位分布。该系统可以利用计算得到的相位分布来分析焦距和像差。

研究人员扩展了他们的研究，测量了在近红外(NIR)光谱中工作的超透镜的相位分布，并确定了样品中缺陷对相位的影响。此外，研究人员还对超透镜在空气和乙醇中的相位分布进行了对比分析，并观察了不同工质中超透镜的相位调制变化。该系统为超透镜的相位表征提供了一种简单的方法，有助于优化超透镜的设计和功能。

据悉，超透镜以其独特的功能和鲜明的物理特性而受到广泛关注，在潜在应用方面展现出巨大潜力。为了进一步优化超透镜的性能，有必要对其相位调制特性进行表征。

附：英文原文

Title: Metalenses phase characterization by multi-distance phase retrieval

Author: Liu, Bowen, Cheng, Jialuo, Zhao, Maoxiong, Yao, Jin, Liu, Xiaoyuan, Chen, Shaohu, Shi, Lei, Tsai, Din Ping, Geng, Zihan, Chen, Mu Ku

Issue&Volume: 2024-08-06

Abstract: Metalens, characterized by their unique functions and distinctive physical properties, have gained significant attention for their potential applications. To further optimize the performance of metalens, it is necessary to characterize the phase modulation of the metalens. In this study, we present a multi-distance phase retrieval system based on optical field scanning and discuss its convergence and robustness. Our findings indicate that the system is capable of retrieving the phase distribution of the metalens as long as the measurement noise is low and the total length of the scanned light field is sufficiently long. This system enables the analysis of focal length and aberration by utilizing the computed phase distribution. We extend our investigation to measure the phase distribution of the metalens operating in the near-infrared (NIR) spectrum and identify the impact of defects in the sample on the phase. Additionally, we conduct a comparative analysis of the phase distribution of the metalens in air and ethanol and observe the variations in the phase modulation of the metalens in different working mediums. Our system provides a straightforward method for the phase characterization of metalens, aiding in optimizing the metalens design and functionality.

DOI: 10.1038/s41377-024-01530-1

Source: https://www.nature.com/articles/s41377-024-01530-1