Ultra-thin optical polarizing films for a near-infrared region using stretched silver island films

We demonstrate optical polarizing films with a larger extinction ratio and aperture by choosing silver (Ag) as metal. We have experimentally found that the Ag island film is most useful for 800 nm. The Ag island films have some advantages over the Au island film. That is: 1) the larger resonance absorption and sharper resonance characteristics, 2) the shorter resonance wavelength, and 3) the larger resonance wavelength shifts. The 0.5 μm-thick polarizing films with an extinction ratio of 30 dB and insertion loss of 1 dB have been fabricated by stretching multilayers consisting of 15 silver island layers with mass thickness of 15 nm. These polarizing films could be useful micro-polarizers for optical sensors or optical communication systems