High Transmittance Broadband THz Polarizer Using 3D-IC Technologies

Abstract

A novel method of fabricating high transmittance and broadband terahertz (THz) polarizers is introduced with several advantages. A polarizer with an approximate 100% transmittance is demonstrated with single central frequency of anti-reflection (AR) layers between 0.5 THz and 2 THz. Broadband polarizer, which has a transmission spectrum of over 70% uniformity, is fabricated by bonding two wafers with different AR layers. The bandwidth of broadband THz polarizer exceeds 1 THz. Extinction ratio of the polarizer is about 30 dB depending on the frequency and Cu wire pitch. The high transmittance and broadband THz polarizer can be achieved through deep reactive-ion etching (DRIE) and wafer bonding. This new fabricating method of THz polarizers has advantages of lower cost, no accurate alignment requirement and robust structure. Therefore, this approach can possibly benefit the mass production of THz optical components in THz applications and even more.