High resolution flash three-dimensional LIDAR systems based on polarization modulation.

Two high resolution flash LIDAR systems based on polarization modulation are demonstrated in this paper. One utilizes a polarization beam splitter (PBS) and two charge coupled device (CCD) arrays; the other utilizes a micro-polarizer array and a CCD array. Compared with the traditional flash LIDAR systems, the main advantage of the presented flash LIDAR systems is replacing high bandwidth detectors with a polarization modulator and low bandwidth detectors. The polarization modulator is used to modulate the polarization state of the received laser pulse in time and the range information can be mapped into the intensity received by the low bandwidth detectors. The distance between the target and the system can be derived from intensity images that can be read out using low bandwidth detectors. Comparisons of the two systems indicate that they have the same range precision. Both demonstrated systems can achieve a high range precision of several millimeters. The system using a PBS and two CCD arrays can obtain higher resolution images, but it is crucial to align the two CCD arrays precisely.