Angle and polarization cooperative sensing based on multilayer film frequency shift characteristics

The coordinated detection of polarization and angle expands traditional one-dimensional intensity information to a high-dimensional intensity-polarization-angle information space, providing more photon detection degrees of freedom for multi-dimensional information sensing. However, the mismatch in measurement accuracy between different photon degrees of freedom limits further its development. In this study, we integrate angle and polarization measurements with spectral detection to construct a multi-degree-of-freedom high-dimensional spectral detection platform based on multi-layer film structures. Distinct from resonance-based nanostructures sensitive to geometric deviations, our lithography-free design leverages topological dark states to ensure superior robustness against structural disorder. We develop two Ag/SiO₂/Si and Ag/SiO₂/Cr/Si film structures with strong multi-dimensional spectral topological robustness. Leveraging the stable existence of extinction ratio (ER) minima across a wide spectral range and the sensitivity of spectral frequency shift properties to incident angle and polarization, we integrate angle and polarization sensing with spectral detection. We experimentally achieve a maximum red shift of the ER peak with angle variation of 130 nm over the wide spectral range of 500–850 nm. Furthermore, by tuning the Cr layer thickness, the operating bandwidth can be extended to 1000 nm. The angular detection sensitivity can achieve a precision of 1° Upon incorporating the Cr layer, the sensitivity and precision are significantly enhanced to 0.7°. The maximum polarization ER between p- and s-polarized light reaches 14.63 dB, with the signal difference consistently exceeding 40%. The polarization detection sensitivity reaches a precision better than 1.1°. The proposed scheme leverages high-sensitivity spectroscopy to unify polarization and angle detection precision, offering a promising strategy for on-chip, multi-dimensional photonic sensing.