A Taxonomic Review of Polarization Direction Metrology: From Rotating-Malus to Vortex Devices

Polarization direction (PD) measurement of linearly polarized light is critical for applications ranging from biomedical diagnostics to aerospace navigation. While traditional rotating-element methods based on Malus' law remain dominant due to their simplicity, they face limitations in speed, accuracy, and mechanical stability. In recent decades, significant advances have been made in non-rotating approaches, including electromagnetic modulation, Faraday rotation systems, and vortex phase retarders enabled by nanofabrication. However, the transition from laboratory prototypes to field-deployable solutions is hindered by disciplinary barriers and the absence of standardized performance benchmarks. This review provides a systematic taxonomy of PD measurement techniques, categorizing them into relative (e.g., optical rotation detection) and absolute (e.g., celestial navigation) measurement paradigms. We analyze six key methodologies—mechanical rotation, electromagnetic modulation, Faraday systems, space-variant polarizers, metasurface, and vortex devices—with comparative evaluation of their accuracy, measurement principle, behind mathematics, temporal resolution, and implementation complexity. By establishing cross-disciplinary connections between measurement physics and engineering requirements, this work serves as a roadmap for selecting optimal PD sensing configurations in emerging application scenarios and accelerating the adoption of next-generation polarization metrology solutions.