Abstract
Metal wire-grid whose period is far less than the illuminating wavelength exhibits strong polarization selectivity within a large field of view over a wide wave length range. Thus it could be used as the polarization-controller in the polarimetric imaging system. For infrared polarimetric imaging system, an aluminum wire-grid on the CaF substrate with period of 200 nm and depth of 100 nm was designed based on effective medium theory. The calculation results demonstrate that the designed wire-grid has the extinction ratio larger than 35 dB within a field of view ±20° over both middle wave infrared (MWIR) (3-5 μm) and long wave infrared (LWIR) (8-12 μm). The aluminum wire-grid was fabricated by electron beam lithography, reactive ion etching and plasma stripping. A clear-cut polarimetric image was obtained when wire-grid was placed in front of a MWIR thermal infrared imager.
Original language | English |
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Article number | 014218 |
Journal | Wuli Xuebao/Acta Physica Sinica |
Volume | 60 |
Issue number | 1 |
Publication status | Published - Jan 2011 |
Keywords
- Effective medium theory
- Polarimetric imaging
- Sub-wavelength diffractive grating