Holographic Stokes-Meter Based Eye-Safe Polarimetric Ladar for Surveillance and Discrimination

We propose to use a Holographic Stokese-Meter (HSM) integrated with a conventional focal plane array (FPA) to develop an eye-safe, polarimetric ladar (PLADAR). The HSM is based on angularly-multiplexed volume holographic gratings, first demonstrated by our company, DOT. Incoming optical signal is split into four components, and the signals observed by corresponding detectors are processed with an FPGA to determine the Stokes Parameters (SP). The SP’s provide a complete characterization of the input signal. For the PLADAR, such an analysis will be performed for each pixel, produced four distinct images, each corresponding to one SP. The detectors used are parts of an FPA developed by our subcontractor, ASC. ASC has developed a flash ladar that uses a single pulse to produce a 3D image. The flash ladar can also be operated to produce conventional, 2D images. The FPA used in this flash ladar will be augmented with the HSM in order to produce the proposed PLADAR. Initially, a commercial pulsed laser at 1571 nm will be used for testing the PLADAR. In addition, we will use our technology of holographic beam combiner (HBC) to develop a laser module that will combine multiple diode lasers in the eye-safe region (around 1550 nm) to produce a light-weight, low-cost source for the PLADAR.