A Comatic Metasurface Hologram for Ultrawide Light Angle Measurement

ABSTRACT Measuring the angle‑of‑arrival (AOA) is critical for emerging applications such as free‑space, inter‑satellite, drone‑based, and underwater optical communication terminals, where rapid coarse alignment over a wide field of view is required. Unlike conventional high‑precision angle metrology (e.g., autocollimators and interferometers) that rely on internal light sources and bulky setups, these scenarios demand compact, low‑cost, passive sensors with direct measurement capability for external light sources. Here, we propose a holographic metasurface that directly visualizes the incident angle of an external laser beam. The metasurface is encoded with a comatic phase profile, generating angle‑dependent holographic fringes that shift linearly with the incident angle. Similar to a comatic lens, the aberration‑free hologram exists exclusively along the optical axis of the metasurface. Experimentally, we demonstrate an optical AOA sensor with an ultrawide measurement range of 90°, a resolution of 0.1°, and a measurement accuracy of 0.064° within ±45°. The device is chip‑scale, passive, and offers direct holographic readout, addressing the longstanding need for compact, low‑cost, wide‑field AOA sensing in portable optical communication and target perception systems.