Investigation of achromatic micro polarizer array for polarization imaging in visible-infrared band

The design and fabrication of a micro polarizer array (MPA) for polarization imaging is described for visible-IR region. The MPA, composed of 1280 × 1024 elements, is designed to be integrated directly onto the CMOS chip. Each micro polarizer consists of a 200-nm-period Al wire grating with the dimension of 5.2 μm × 5.2 μm, and the performance of gratings with finite number of periods and gradient ridge-length has been thoroughly investigated. The grating ridge of each polarizer orients four different directions offset by 45° which determines different polarization directions correspondingly. Initial test and experiment for the MPA are performed and the crosstalk caused by diffraction is discussed.