title: Transmittance enhancement of a wire-grid polarizer by antireflection coating.
abstract: We examined the effect of an antireflection (AR) coating to enhance the TM transmittance of the wire-grid polarizer. The polarization transmission spectra were calculated using the rigorous coupled-wave analysis. As a result, we verified that an AR film should be inserted between a wire-grid and a Si substrate as regards the TM transmittance and the polarization function. Based on the simulation results, we fabricated a tungsten silicide (WSi) wire-grid polarizer with SiO films on both sides of the Si substrate. The transmittance exceeded 80% at a 4-5 microm wavelength range, although the theoretical transmittance of Si substrate is 54% and the ratio of the TM and TE transmittances reached 24 dB at a 3 microm wavelength when the WSi grating has a 300 nm thickness, a 400 nm period, and a fill factor of 0.6. Wire-grid polarizers with higher transmittance and larger extinction ratio can be obtained by adjusting the AR film thickness, the fill factor, and the thickness of the WSi grating.
authors.affiliation: National Institute of Advanced Industrial Science and Technology, Midorigaoka, Ikeda, Osaka 563-8577, Japan.
authors.forename: Itsunari
authors.initials: I
authors.lastname: Yamada
authors.forename: Kenji
authors.initials: K
authors.lastname: Kintaka
authors.forename: Junji
authors.initials: J
authors.lastname: Nishii
authors.forename: Satoshi
authors.initials: S
authors.lastname: Akioka
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yamagishi
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Saito