近日，美国华盛顿大学的Arka Majumdar&Aamod Shanker及其研究团队取得一项新进展。经过不懈努力，他们利用超透镜实现定量相位成像内窥镜。相关研究成果已于2024年11月8日在国际知名学术期刊《光：科学与应用》上发表。

该研究团队利用氮化硅双曲面超透镜固有的色差，在相干光纤束的尖端实现了定量相位成像。该研究采用的方法利用光谱复用技术，通过彩色相机单次拍摄即可从多个离焦平面中恢复相位信息。在实验中，研究人员使用的0.5毫米孔径的超透镜在与内窥镜光纤束配合时，展现出了强大的定量相位成像能力，具有28°的视场和0.2π的相位分辨率（在空气中约相当于0.1个波长）。

由于光谱功能直接编码在成像透镜中，因此该超透镜同时起到了聚焦元件和光谱滤波器的作用。配合简单的计算后端，即可实现实时操作。相较于传统的内窥镜相位成像方法，如多次采集、干涉对准或机械扫描，本研究所提出的基于超透镜的定量相位成像技术完全克服了这些关键局限。

据悉，定量相位成像（QPI）通过强度测量来恢复光的精确波前。可以从这些量化的相位偏移中提取出透明微观物体的形貌和光密度图。

附：英文原文

Title: Quantitative phase imaging endoscopy with a metalens

Author: Shanker, Aamod, Frch, Johannes E., Mukherjee, Saswata, Zhelyeznyakov, Maksym, Brunton, Steven L., Seibel, Eric J., Majumdar, Arka

Issue&Volume: 2024-11-08

Abstract: Quantitative phase imaging (QPI) recovers the exact wavefront of light from intensity measurements. Topographical and optical density maps of translucent microscopic bodies can be extracted from these quantified phase shifts. We demonstrate quantitative phase imaging at the tip of a coherent fiber bundle using chromatic aberrations inherent in a silicon nitride hyperboloid metalens. Our method leverages spectral multiplexing to recover phase from multiple defocus planes in a single capture using a color camera. Our 0.5mm aperture metalens shows robust quantitative phase imaging capability with a 28° field of view and 0.2π phase resolution (~0.1λ in air) for experiments with an endoscopic fiber bundle. Since the spectral functionality is encoded directly in the imaging lens, the metalens acts both as a focusing element and a spectral filter. The use of a simple computational backend will enable real-time operation. Key limitations in the adoption of phase imaging methods for endoscopy such as multiple acquisition, interferometric alignment or mechanical scanning are completely mitigated in the reported metalens based QPI.

DOI: 10.1038/s41377-024-01587-y

Source: https://www.nature.com/articles/s41377-024-01587-y