Material detection with a CCD polarization imager

Abstract

We present a novel polarization image sensor by monolithically integrating aluminum nanowire optical filters with CCD imaging array. The CCD polarization image sensor is composed of 1000 by 1000 imaging elements with 7.4μm pixel pitch. The image sensor has a dynamic range of 65dB and signal-to-noise ratio of 60dB. The CCD array is covered with an array of pixel-pitch matched nanowire polarization filters with four different orientations offset by 45°. Raw polarization data is presented to a DSP board at 40 frames per second, where degree and angle of polarization is computed. The final polarization results are presented in false color representation. The imaging sensor is used to detect the index of refraction of several flat surfaces.