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Proceedings Paper

Grooved infrared polarizers with a reduced reflectance
Author(s): Itsunari Yamada; Junji Nishii; Mitsunori Saito
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Paper Abstract

We fabricated an infrared wire-grid polarizer that was made of a tungsten silicide (WSi) grating on a Si substrate. The photolithography by the use of the two-beam interference was conducted for generating the short-period grating structure. This photoresist pattern was used as a mask for the reactive ion etching of the WSi coating and the Si substrate. Consequently, we could fabricate the WSi/Si grating with 400-nm period and 550-nm depth that acted as a wire-grid polarizer. The transmittance of TM polarization was 58% at 4-μm wavelength, which exceeded the theoretical transmittance of Si (54%). This enhancement of the transmittance was caused by the reduction in the reflectance due to the subwavelength-grating structure. The extinction ratio at 2.7-μm wavelength was 20 dB. We also measured the extinction coefficient κ of WSi, and verified that WSi was a suitable polarizing material in the mid-infrared range.

Paper Details

Date Published: 8 January 2007
PDF: 11 pages
Proc. SPIE 6414, Smart Structures, Devices, and Systems III, 64141V (8 January 2007); doi: 10.1117/12.695729
Show Author Affiliations
Itsunari Yamada, Ryukoku Univ. (Japan)
Junji Nishii, National Institute of Advanced Industrial Science and Technology (Japan)
Mitsunori Saito, Ryukoku Univ. (Japan)


Published in SPIE Proceedings Vol. 6414:
Smart Structures, Devices, and Systems III
Said F. Al-Sarawi, Editor(s)

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