LINEAR-POLARIZATION UNIFORMITY MEASUREMENTS TAKEN WITH AN IMAGING POLARIMETER

Four types of polarizers are experimentally evaluated and compared for the uniformity of their transmission axis orientations and the contra st ratio and their spatial variation. Representative samples of calcit e Glan-Thompson polarizers, polarizing beamsplitters, silver glass pol arizers, and stretched polymer polarizers are characterized at 850 nm using a rotating polarizer imaging polarimeter. The sample Glan-Thomps on polarizers show the highest contrast ratios and greatest uniformity of transmission axis. Silver glass polarizers and stretched polymer p olarizers show intermediate contrast ratios, but all samples of both s how a systematic variation of the transmission axis orientation with a magnitude of several tenths of a degree, The polarizing beamsplitter cube samples have very good uniformity of transmission axis but the sm allest contrast ratios with noticeable spatial variations of contrast.