Four-dimensional imaging based on a binocular chiral metalens

In this Letter, we present a binocular chiral metalens (BCM) device designed for four-dimensional (4D) imaging, which integrates both three-dimensional spatial perception and polarization detection. The BCM consists of two identical monocular metalenses that spatially separate left- and right-handed circularly polarized (LCP and RCP) light. When integrated with a commercial camera, the metalenses enable simultaneous measurement of the depth and polarization information. Numerical simulations and experimental results demonstrate that the BCM can achieve a circular polarization extinction ratio (CPER) of 29.2 dB and an average 3D reconstruction error of 4.09%. The proposed system paves a pathway for multi-dimensional imaging, with significant potential in applications in security, surveillance, and future advancements in more complex imaging tasks across other electromagnetic bands, including terahertz and infrared regimes.