Optical characterization of wiregrid micropolarizers designed for infrared imaging polarimetry

摘要

We report the optical characterization of a metal wiregrid micropolarizer array for IR imaging polarimetry.nThe micropolarizers are designed for operation in the 1.5–5.0 u0001m band with a specially designed thin SiO2nlayer between the silicon substrate and the wiregrids to improve the performance at the shorter wave-nlengths. Deep-UV projection lithography is used to fabricate 140-nm-deep wiregrids with a 400 nm period.nThe extinction ratio and the transmission coefficient are measured with a tunable IR laser. A TM transmis-nsion coefficient greater than 70% with an extinction ratio greater than 104 is achieved for the midwave-IRnregion while maintaining an extinction ratio better than 102 for the near-IR region above 1.5 u0001m. © 2008nOptical Society of America