<title>Evaporative Thin Metal Films As Polarizers</title>

Abstract

Thin metal films have been fabricated by vacuum evaporation, which polarize transmitted light at near-infrared and visible wavelengths. Polarization of normal-incidence light was observed for silver, gold and copper films made by this technique. The polarizing films were produced by directing a beam of metal atoms onto the smooth surface of an optically transparent substrate at a large angle of incidence. The film structure revealed by electron-microscope examination is a dense array of parallel metal whiskers aligned opposite the direction of the incident metal atom beam. Polarization is produced by the hertzian parallel-wire effect, which is also the polarization principle of the conventional wire-grid polarizer. The resulting polarizer material can be produced in sheet form or applied as a coating to optical elements.