Chip-integrated Metasurface Polarimetric Imaging Sensor and Applications

Polarization imaging and polarization microscopy is of great interest in industrial inspection, defense, biomedical and clinical research, food safety, etc. An ideal polarization imaging system suitable for versatile applications should be full-Stokes, compact, broadband, fast, and highly accurate within a large operation angle. However, such a polarization imaging system remains elusive among state-of-the-art technology. Recently, flat optics based on metasurfaces have been explored for polarization detection and imaging. Compared with state-of-art, metasurface-based solutions have the advantages of compactness, great design flexibility, and feasibility for on-chip integration. This dissertation reports a dual wavelength (630 to 670nm and 480nm to 520nm) chiral metasurfaces featured with sub-wavelength dimension, extinction ratio over 10 across a broad operation bandwidth (175nm) and efficiency over 60%, which can be used for detection and generation of circular polarization (Chapter 2). This dissertation then reports a chip-integrated full-Stokes polarimetric Complementary metal–oxide–semiconductor (CMOS) imaging sensor based on metasurface polarization filter arrays (MPFA) mentioned above. The sensor has high measurement accuracy of polarization states with an angle of view up to 40°. Calibration and characterization of the device are demonstrated, whereby high polarization states measurement accuracy (measurement error <4%) at incidence angle up to ±20° and full Stokes polarization images of polarized objects are shown. (Chapter 3). A scalable fabrication approach based on nano imprint lithography is demonstrated, with improved fabrication efficiency, lower cost, and higher optical performance up to 10 times compared to EBL process. (Chapter 4). Several polarization imaging applications including a dual-camera full-Stokes underwater polarization navigation system are discussed. Polarization mapping under clear sky and clear water is demonstrated for proof concept. Enhancing contrast of objects through turbid water and polarization images of silver dendrites are also discussed (Chapter 5). Though distinctive in its advantages in rich polarization information, most existing Mueller matrix microscope (MMM) operate at single mode, narrow bandwidth with bulky components. This dissertation reports a compact, dual wavelength, dual mode MMM with satisfactory measurement accuracy (Mueller matrix (MM) measurement error≤ 2.1%) using polarimetric imaging sensor mentioned previously, MM imaging of photonic structures, bio-tissues, etc are demonstrated for proof of concept (Chapter 6).