Optical properties of very thin metal films for laminated polarizers

Periodic metal-dielectric laminated layers have potential for making micropolarizers with high extinction ratios. In this paper we investigate the optical characteristics of metal films for a laminated polarizer (Lamipol). The optical characteristics of very thin metal films (<10 nm) are different from those of the bulk metal because of the size effect, oxidation, defects, or impurities in films. Changes in optical characteristics are experimentally studied. The relationship between optical characteristics of Lamipols, metal layer morphology, and the condition of film deposition is investigated. Aluminum films made with an improved sputtering system have nearly the same optical parameters as those of bulk Al. It is expected that low loss/ high extinction Lamipols can be made by alternative layers of the deposition of Al and SiO(2) using such an improved system.