Nonlocal flat optical filter for color conversion-assisted angle sensing

Angular incoming light information is crucial for light-field detection to provide better scene awareness. However, current angle-sensing techniques often rely on complex light-sensing elements and require complex post-processing. Here, we demonstrate a compact and straightforward approach for angular detection based on a nonlocal flat optical filter. Combined with a commercially available CMOS sensor array, such a filter can convert light rays from various directions into distinct color outputs, with experimental and theoretical angular detection resolutions up to 0.1° and 0.01°, respectively. We experimentally demonstrate the sensor’s capability across single wavelengths (550 nm and 680 nm), a broad wavelength range (400–800 nm), and multiple polarization states ( s -, p -, or unpolarized) and in both parallel and diverging light conditions. This angle-sensing approach expands the scope of nonlocal flat optics for light detection, ushering in opportunities for ultra-compact and fast-speed angle sensors.