Submicron patterning of conductive polymers for use in infrared polarizers

Conductive polymers have become an extremely useful class of materials for many optical applications. Additionally, advanced fabrication methods have led to the development of metal based micro-wiregrid polarizers utilizing submicron features. Adapting these fabrication approaches for use with polymer materials leads to optical polarizers with unique properties. The patterning of conductive polymers with the small features required for wiregrid polarizers leads to several challenges. First, the deposition of the polymer must provide a layer thick enough to provide a polarizer with a useful extinction ratio that also has high conductivity and environmental stability. Two deposition approaches have been investigated, spin coating and electrochemical growth, and results of this work will be presented. Also, the polymers considered here are not compatible with basic photoresist processes. Various tactics have been examined to overcome this difficulty including the use of hard bakes of the polymer, protective overcoats and patterned growth. The adaptations required for successfully patterning the polymer will be reviewed. Finally, fabricated devices will be shown and their optical characterization presented.