Double-layer wire grid polarizer for improving extinction ratio

We proposed a polarizer which has high extinction ratio for the terahertz light. The polarizer has a double-layer wire grid for improving the extinction ratio. A space between these wire grid layers is set to be approximately one-hundredth of the wavelength of interest in order to eliminate the harmful Fabry-Perot interference. We fabricated the double-layer wire grid polarizer and measured transmittance of the fabricated polarizer. Comparing the transmittances of the fabricated polarizer and that of a polarizer with a space that is comparable to the wavelength of interest, we confirmed that the Fabry-Perot interference was eliminated. The extinction ratio of the fabricated polarizer was on the order of 10⁴ for range from 0.3 to 1.7 THz.