Broadband unidirectional visible imagers using wafer-scale nanomanufacturing

We report a broadband, polarization-insensitive unidirectional imager that operates within the visible spectrum, capable of high-efficiency image transmission in one direction while effectively suppressing image formation in the reverse direction. This unidirectional imager incorporates multilayer diffractive structures fabricated through wafer-scale lithography on high-purity fused silica, offering high optical transparency, thermal stability and ultra-low loss. This device features nanoscale diffractive layers patterned on both sides of a 6-inch wafer to form a two-layer diffractive processor. We experimentally demonstrated unidirectional imaging at three distinct wavelengths (467.5, 525, and 627.5 nm). The results exhibited high-fidelity image formation in the forward direction and significant suppression of image formation in the reverse direction, closely matching simulations. Moreover, experiments under various polarization states validated the system’s polarization-insensitive performance. This work demonstrates the first wafer-scale fabrication of multilayer diffractive processors specifically designed for visible imaging, enabling scalable and high-throughput fabrication.