Broadband high-contrast polarization detection via photoacoustic sensing

Light polarization states are the intrinsic properties of light and are widely exploited in fields such as remote sensing, computing, and medical imaging. Conventional photoelectric sensors used for polarization detection are fundamentally constrained by the wavelength-dependent bandgap of their constituent materials, and therefore hinder their ability to meet the practical demands of broadband high-contrast polarization detection. To address this limitation, we develop a time-division photoacoustic sensing-based polarization detection (PSPD) scheme that exploits the polarization-dependent photoacoustic response of an optically anisotropic absorbing transducer at a wide spectral range, enabling broadband polarization detection from the visible to the second near-infrared window (NIR-II) with high polarization contrast. Moreover, leveraging the depth-resolved nature of the photoacoustic effect, we show that the z-axis extension of PSPD can facilitate fast multiplexed polarization readout toward polarization imaging. The proposed PSPD offers a versatile platform for fast polarization measurements, enabling future developments in polarization imaging and advanced optical sensing applications.