Metasurface-enabled single-shot and complete Mueller matrix imaging

Nature Photonics | Volume 18 | July 2024 | 704–712 704 nature photonics Article https://doi.org/10.1038/s41566-024-01426-x Metasurface-enabled single-shot and complete Mueller matrix imaging Aun Zaidi    1  , Noah A. Rubin    1,2, Maryna L. Meretska    1,3, Lisa W. Li    1, Ahmed H. Dorrah    1, Joon-Suh Park    1 & Federico Capasso    1  When light scatters off an object, its polarization, in general, changes—a transformation described by the object’s Mueller matrix. Mueller matrix imaging is an important technique in science and technology to image the spatially varying polarization response of an object of interest, to reveal rich information otherwise invisible to traditional imaging. Here we conceptualize, implement and demonstrate a compact Mueller matrix imaging system—composed of a metasurface to produce structured polarization illumination and a metasurface for polarization analysis—that can, in a single shot, acquire all 16 components of an object’s spatially varying Mueller matrix over an image. Our implementation, which is free of any moving parts or bulk polarization optics, should enable and empower applications in real-time medical imaging, material characterization, machine vision, target detection and other important areas. Traditionally, imaging in optics is understood to capture the intensity of a light field. Imaging then usually quantifies an object’s spatially vary- ing intensity response under given illumination conditions, providing a simplified description of a more complex light–object interaction. The measurement of optical intensity, being a time-averaged square modulus of the electric field vector, necessarily ‘flattens’ many degrees of freedom of light and natural scenes. Imaging beyond intensity in a way that can recover a fuller picture of light and light–matter interac- tion, and the optical hardware to enable this imaging, are overarching goals of research in optics. In what is perhaps the simplest omission, intensity-only imaging is necessarily blind to the phase of coher- ent light, an issue addressed by techniques such as phase contrast microscopy1, which enables the direct visualization of transparent living microbes. Moreover, as a transverse electromagnetic wave, light is vectorial in nature: light’s polarization state, which is also absent in traditional intensity-only ima