Polarization-Resolved Plant Tissue Imaging Using a Metalens Array

Polarization-sensitive imaging enhances contrast and reveals structural features in biological tissues that are often missed by intensity-only methods, but its adoption is limited by bulky optics. We present a compact silicon-rich nitride (SRN) metalens array for high-resolution, polarization-resolved imaging of plant tissue at the chlorophyll absorption peak (660 nm). The array integrates orthogonally polarization-sensitive metalenses to simultaneously capture x- and y-linearly polarized transmission images, enabling real-time, label-free assessment of plant microstructure and stress-related changes. Polarization fusion and difference mapping reveal structural anisotropy and pigment absorption variations in both healthy and stressed leaves. The SRN metalens, designed via an inverse-design approach using birefringent meta-atoms and fabricated through complementary metal–oxide–semiconductor (CMOS)-compatible processes, achieves a large numerical aperture (NA), high transmission, and spectral alignment with biological chromophores. This work demonstrates a benchtop proof-of-concept for polarization-resolved imaging using an SRN metalens array, showing that polarization contrast can enhance tissue feature visibility beyond intensity-only imaging. The approach holds potential for biomedical and agricultural applications, where the detection of subtle polarization-dependent changes could enable early diagnosis and tissue characterization.