Metasurfaces for 3D Polarization Imaging at Long Range

Sea-surface target detection and identification at long ranges is a multifaceted challenge due to the complex, dynamic nature of maritime environments. Environmental factors such as wave clutter, fog, and sun glitter combined with a small target hinder the overall effectiveness of imaging-based target detection systems. To overcome these challenges, systems using polarization information have been developed to improve detection reliability, and the addition of depth information can potentially further aid in discriminating targets. Current 3D polarization imaging systems are limited in size, weight, power, and cost (SWaP-C) and have a low signal-to-noise ratio (SNR). In this work, we will develop a 3D polarization imaging system using meta-optics for drastically reduced SWaP-C and improved SNR. Meta-optics are periodic, two-dimensional arrays with spatially variant subwavelength features that provide arbitrary control of phase, amplitude, and polarization. We will investigate two meta-optic design concepts: 1) a narrowband large aperture metasurface and 2) a broadband hybrid lens system containing meta-optics and refractive lenses. Quantitative metrics such as modulation transfer function and the depth accuracy will be assessed over the entire field of view and operational bandwidth. We will compare the advantages of each design and down-select the more promising design for small-scale fabrication and characterization experiments. By the end of Phase I, we expect to have a demonstrated meta-optic concept, allowing us to further develop and experimentally demonstrate this technology in Phase II and beyond.