Metal-film subwavelength-grating polarizer with low insertion losses and high extinction ratios in the terahertz...

A metal-film subwavelength-grating polarizer with high performance in the terahertz region is presented. The polarizer was obtained by depositing a thin Au film on a resin grating with a triangular cross section duplicated from a metal mold by using the imprinting method. Microstructural parameters were investigated in detail. Measured insertion losses were less than 0.5 dB in the frequency range of 0.5-3 THz, while extinction ratios were 50 dB in the range of 0.5-2.3 THz. The proposed fabrication method is suited to mass production of large-aperture robust polarizers.