Optical EngineeringLinear polarization uniformity measurements taken with an imaging polarimeter
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Four types of polarizers are experimentally evaluated and compared for the uniformity of their transmission axis orientations and the contrast ratio and their spatial variation. Representative samples of calcite Glan-Thompson polarizers, polarizing beamsplitters, silver glass polarizers, and stretched polymer polarizers are characterized at 850 nm using a rotating polarizer imaging polarimeter. The sample Glan-Thompson polarizers show the highest contrast ratios and greatest uniformity of transmission axis. Silver glass polarizers and stretched polymer polarizers show intermediate contrast ratios, but all samples of both show 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 smallest contrast ratios with noticeable spatial variations of contrast.